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The authors analyze phytoplankton diversity of a small urban wetland of Meghalaya to assess biodiversity and limnology interest of small water bodies. This “slightly acidic-circumneutral, demineralized and soft water” subtropical wetland reveals diverse phytoplankton (64 species), indicates high desmid richness and highlights the speciose littoral constellations of up to 55-58 species per sample. Phytoplankton comprises dominant quantitative component of net plankton and registers Charophyta dominance; Chlorophyta > Bacillariophyta > Dinozoa > Chrysophyta > Cyanobacteria depict sub-dominance, and Euglenozoa and Cryptophyta show poor abundance at the littoral and semi-limnetic regions. The richness of phytoplankton and abundance of phytoplankton, Charophyta, Chlorophyta, Dinozoa, Chrysophyta and Cyanobacteria follow bimodal spatio-temporal variations. Closterium, Cosmarium, Staurastrum, Micrasterias, Netrium, Staurodesmus and Scenedesmus are notable genera, and 14 species collectively influence phytoplankton abundance. Phytoplankton registers high species diversity, lower dominance and high evenness. Amongst 15 abiotic factors, only the rainfall and sulphate exert notable influence individually, while the canonical correspondence analysis registers lower cumulative influence of the selected 10 factors on the littoral and semi-limnetic phytoplankton assemblages. This study merits interest for neglected biodiversity and ecology of small aquatic biotopes of India and urban wetlands in particular.

The spatio-temporal variations of phytoplankton diversity of the ‘de-mineralized’ sacred Thadlaskein Lake of Meghalaya state of northeast India are monitored based on analyses of the littoral and limnetic assemblages. Our study reveals a total of 51 species, depicts notable desmid diversity, and records the speciose constellation of 49 species per sample. Phytoplankton indicates importance vis-a-vis net plankton abundance and exhibits quantitative dominance of Charophyta; Chlorophyta > Bacillariophyta > Dinozoa > Chrysophyta are sub-dominant groups, and Cyanobacteria and Euglenozoa record poor densities. Closterium spp., Cosmarium spp., Scenedesmus spp. and Staurastrum spp. are noteworthy taxa, and eleven species contribute notably to phytoplankton abundance. Our results depict high species diversity, lower dominance and high evenness. Individual abiotic factors exert the differential spatial influence on phytoplankton, and register the relative importance of the rainfall, transparency and total hardness, while the CCA registers the moderate cumulative influence of 10 abiotic factors on the littoral and limnetic assemblages. The spatial variations of various aspects of phytoplankton diversity and the influence of abiotic factors are hypothesized to the habitat heterogeneity amongst the two regions. The present study is a useful contribution to the phytoplankton diversity of India and that of the subtropical lacustrine environs of the country.

We assess biodiversity status of Rotifera known from India to-date based on our studies from various regions of this country and evaluation of other viable records, and highlight notable features of biogeography and richness. The Indian fauna reveals 434 valid species belonging to 68 genera and 25 families and thus indicates the most biodiverse Rotifera vis-à-vis south and Southeast Asia, and records ~25% and ~41% species of global and regional biogeographic interest. It depicts the littoral-periphytic nature, broadly tropical character, the limited reports of cold-water species from the sub-Himalayan and Himalayan latitudes, paucity of the endemics and Bdelloids, and cryptic diversity awaits analyses. The richest diversity and distinct biogeographic identity of Rotifera of Northeast India (NEI) is attributed to location of this region in the ‘Himalayan and Indo-Burmese’ biodiversity hot-spots, ‘Assam gateway’ – the biogeographic corridor, and the ‘Rotiferologist effect’. Regional disparity and spatial heterogeneity of biodiversity elsewhere from India are attributed to the limited sampling, inadequate collections from diverse ecosystems, unidentified species, and paucity of attention on smaller species. The biodiverse rotifer assemblages of the floodplain lakes including Deepor Beel and Loktak Lake, the two Ramsar sites and globally megadiverse ecosystems, are hypothesized to habitat diversity of these ecotones, while ‘Rotifera paradox’ depict speciose constellations per sample. The species-rich small floodplain and urban wetlands focus interest on rotifer diversity in small water bodies. We estimate more diverse Indian Rotifera following analyses of collections from underexplored and unexplored regions and ecosystems, and the bdelloid and sessile rotifers using integrative taxonomic approaches.

This study monitors the spa-tio-temporal variations of phytoplankton of a soft-water and de-mineralized reservoir of Meghalaya state of northeast India. Phyto-plankton assemblages of the littoral and limnetic regions reveal total 36 species and diverse desmids, and con-tribute dominantly to net plankton abundance. Our results record the quantita-tive importance of Charo-phyta > Bacillariophyta > Dinophyta and Charophyta > Dinophyta, and the ‘spe-cialist’ nature of 11 and six species at the littoral and limnetic regions, respective-ly. Staurastrum spp. and Cosmarium spp. are notable taxa. Phytoplankton indi-cates moderate species di-versity and depicts domi-nance and evenness varia-tions. The individual abiotic factors exert differential in-fluence on various taxa at the two regions and the ca-nonical correspondence analysis registers 73.02 and 71.14% cumulative influ-ence of 10 abiotic factors on the littoral and limnetic as-semblages, respectively. The spatial differences of phytoplankton composition, richness, abundance, im-portant groups and taxa, specialist species, diversity indices and the influence of individual abiotic factors are hypothesised to habitat heterogeneity amongst the sampled regions. This study records notable temporal differences of phytoplank-ton richness, abundance, di-versity and the role of abiot-ic factors vis-a-vis the lim-ited survey of November 1990–October 1991.

Rotifera assemblages of small floodplain wetlands (dobas or dubies) of lower and upper regions of the Brahmaputra river basin of Assam state of northeast India (NEI) reveal 157 species, belonging to 34 genera and 18 families, and highlight notable speciose constellation of up to 50 species/sample. One species, each is new to the Oriental region and Assam, and species of global and regional biogeographic interest form notable fractions. The biodiverse rotifer fauna and various interesting species are hypothesized to habitat diversity of the sampled dobas or dubies, impact of `the Assam-gateway’- an important biogeographic corridor of India, and location of the study area in the Indo-Burmese biodiversity hot-spot. Lecanidae and Lepadellidae are species-rich families, both of lower and upper Assam wetlands; upper Assam wetlands, in particular, are characterized by a distinct paucity of the Brachionidae and Brachionus spp., the relative paucity of Trichocerca, Keratella and Mytilina species, rare occurrence of Asplanchna and Filinia species, and lack of species of Conochilidae and Hexarthridae. Our results indicate the littoral-periphytic nature and tropical character of the rotifers. Overall, this study is an important contribution to Rotifera biodiversity of small lentic habitats of India, Asia and that of the tropics and subtropics.

Nongmahir reservoir of Meghalaya state of northeast India (NEI), sampled at the littoral and limnetic regions, revealed fairly biodiverse zooplankton of total 56 species with peak consortium (52 species) in January collection from the littoral region. The richness indicated spatial monthly variations and heterogeneity at the two regions mainly influenced by Rotifera. The ‘soft and de-mineralized waters’ resulted in low zooplankton abundance. Copepoda > Rotifera with Cyclopidae > Brachionidae influenced zooplankton, and Mesocyclops leuckarti > Keratella cochlearis > Ascomorpha ovalis > Microcyclops hyalinus are notable species at the littoral region. The limnetic region recorded Rotifera dominance, and importance of Brachionidae > Cyclopidae and K. cochlearis > Conochilus unicornis >M. leuckarti >A. ovalis > Asplanchna priodonta > Polyarthra vulgaris. Zooplankton recorded moderate species diversity and notable differences of evenness and dominance. The spatial monthly differences of richness, abundance and diversity indices of zooplankton, and importance of notable taxa are hypothesised to habitat heterogeneity of the two regions. Our results also indicated limited and differential influence of individual abiotic factors on zooplankton taxa, while the canonical correspondence analysis registered high cumulative influence of 10 abiotic factors on the littoral (80.62%) and limnetic (74.79%) assemblages along axis 1 and 2. This study highlighted distinct temporal variations of different diversity parameters than our preliminary survey of June 1995–May 1996.

Limnological survey of a small urban wetland of Meghalaya state of northeast India (NEI), undertaken at the littoral and semi-limnetic stations, reveals one of the biodiverse zooplankton assemblages (148 species belonging to 72 genera and 30 families) known from any lentic environ of the Indian sub-region. The speciose nature, peak constellation/sample of 83 zooplankton species, and diverse Rotifera (90 species) are hypothesized to environmental heterogeneity of this urban wetland in contrast to the general pattern of reduced richness expected in highly modified urban aquatic environments. The soft and de-mineralized waters are characterized by low zooplankton abundance. This study records high species diversity and evenness, and low dominance attributed to low and equitable abundance depicts ‘generalist’ nature of all species. Rotifera > Cladocera and Chydoridae > Lecanidae > Lepadellidae > Daphniidae are important at both stations, and Testudinellidae, Trichocercidae, and Macrothricidae are notable at the littoral station. Individual abiotic factors exert limited and differential spatial influence on various taxa, while the CCA registers a high cumulative influence of 10 abiotic factors on the littoral (87.37%) and semi-limnetic (75.81%) zooplankton assemblages. The spatial variations of composition, richness, similarities, abundance, diversity indices, and of the influence of individual abiotic factors are hypothesized to habitat heterogeneity amongst the sampled stations.

Hydrobiological survey of a ‘soft-water’ and ‘highly de-mineralized’ reservoir of Meghalaya state of northeast India is undertaken to analyze zooplankton diversity with reference to the spatio-temporal variations and influence of abiotic factors. The littoral and limnetic zooplankton assemblages of this subtropical reservoir without aquatic vegetation reveal total 36 species, and record lower abundance, quantitative dominance of Rotifera, sub-dominance of Cladocera and Copepoda and moderate species diversity. Keratella cochlearis, Bosmina longirostris, Polyarthra vulgaris, Mesocyclops leuckarti, Conochilus unicornis and Asplanchna priodonta influence abundance, species diversity, dominance and equitability of zooplankton. We report differential spatial influence of individual abiotic factors with the relatively more importance at the limnetic region, and the canonical correspondence analysis registers 72.5% and 78.8% cumulative influence of 10 abiotic factors on the littoral and limnetic assemblages, respectively. The spatial differences of various diversity aspects and the influence of abiotic factors suggest habitat heterogeneity amongst the two regions. This study is a useful contribution to zooplankton diversity of the subtropical environs, and soft and de-mineralized waters in particular. Our results mark a distinct contrast to the lowest richness and abundance of zooplankton noted from India vide the preliminary 1990-91 survey of this reservoir.

The study aims to ascertain the hypothesis on the rich rotifer biodiversity of the floodplain lakes (beels) of the Brahmaputra river basin and to use these metazoans to assess trophic status or to characterize habitat variations of wetlands. The plankton samples collected from four beels of lower Assam revealed 160 Rotifera species belonging to 35 genera and 19 families. The richness is of biodiversity value as ~38.0% and ~57.0% of the rotifer species known till date from India and northeast India (NEI), respectively. One species each is new to the Oriental region and NEI, and three species are new to Assam; 23 species merit global biogeography interest and several exhibit distribution values in the Indian sub-region. The diverse Lecanidae > Brachionidae > Lepadellidae > Trichocercidae and speciose littoral-periphytic Lecane > Lepadella > Trichocerca, and richness of Brachionus spp. following removal of aquatic macrophytes are noteworthy. Overall rotifer composition showed homogeneity amongst beels while lower monthly richness and community similarities affirmed heterogeneity within individual beels. We propose L/B quotient based on Lecane: Brachionus species ratios to characterize habitat variations of the sampled wetlands. Sladecek’s B/T quotient based on Brachionus: Trichocerca species ratios affirmed general’ meso-trophic’ status of different beels. Our results provided little insight on the influence of individual abiotic factors but the canonical correspondence analyses asserted higher cumulative influence of ten abiotic parameters on Rotifera richness in each beel.

Small lentic ecosystems are hypothesized to be interesting habitats for metazoan diversity. This study is undertaken to document Rotifera of small freshwater bodies of south Andaman, India. A total of 112 species (S), belonging to 32 genera and 19 families, recorded in our intensive February 2017 collections, indicate rich and diverse assemblage of the taxon. Total richness comprises ~ 27 % of the rotifer species known from India and thus affirms biodiversity interest and habitat diversity of the sampled habitats. This report adds 42 species, seven genera and three families to the taxa reported till date from freshwaters of the Andaman and Nicorbar islands. Rotifera meta-analysis indicates distinct increase in richness of Lecanidae > Brachionidae > Trichocercidae and two-fold increase in Brachionus species. The biogeographically interesting elements comprise 8.0 % of S and several species indicate regional distribution importance. The rotifer fauna shows high richness of cosmopolitan species (~68% of S) and a number of tropical and subtropical species (~22 % of S). The present study highlights distinct scope to augment Rotifera diversity of the Andaman and Nicorbar islands freshwaters vis-à-vis intensive sampling of varied habitats.

The status of diversity of Lepadellidae of India is reviewed based on our studies and the published literature and 42 valid species are reported. These comprise ∼26.0 and 71.0% of the richness of the family known globally and from the Oriental region, respectively, and nearly 10.3% of the Indian Rotifera. One species is new to India and one species is new to northeast India (NEI). The interesting taxa include one Oriental endemic, two Indian endemics, and four Paleotropical species, while several species exhibit regional distributional importance. Low endemicity and richness of cosmopolitan species (∼76.0%) are characteristics of the Indian Lepadellidae. This taxon is relatively more known from certain states of northeast, east, and south India but remains poorly studied from rest of this country. An update on Lepadellidae from India, and the Himalayan region and Western Ghats “hot-spots” in particular; and analysis of cryptic diversity in Colurella adriatica – colurus, C. obtusa, C. uncinata, Lepadella acuminata, L. ovalis, and L. patella merit further interest for the rotifer biodiversity and biogeography.

This study extends our previous work to investigate the planktonic rotifers of floodplain lakes (locally called as beels or pats) of Northeast India (NEI) and reviews the known rotifer diversity from the seven states of this region. To do this we examined plankton samples from numerous sites from different states, including 30 floodplain lakes (beels) of Assam and 15 floodplain lakes (pats) of Manipur. This survey yielded 238 species, making the region of NEI one of the most specious and diverse (50 genera and 23 families) of the Indian subcontinent. Occurrence of four Australian and Asian, 10 Oriental, 13 Paleotropical, two Holarctic, two Indian pandemics, 12 Eastern Hemisphere elements, and several species of regional distribution importance are distinctive features of this rotifer assemblage. The beels or pats of NEI are Rotifera rich habitats with Deepor Beel and Loktak Lake (two Ramsar sites) as globally important wetlands, and Assam (>50.0% of the Indian species) recorded highest richness amongst all states of this country. While explaining some 63–74% of the variation of the rotifer assemblage along two axes, Canonical Correspondence Analysis yielded little insight regarding the influence of individual abiotic parameters on their diversity. This study from Northeast India, a part of the Himalayan and Indo-Myanmar “hotspots,” is of special biodiversity interest.

The plankton and semiplankton samples examined from a subtropical wetland of Shillong, Meghalaya, Northeast India (NEI), revealed seven new records of rotifers belonging to six genera and six families. These include five species new to the Indian Rotifera and two species new to the rotifer fauna of NEI, thus meriting interest in terms of biodiversity and distribution. All the species are illustrated to warrant validation. While a detailed account of the rich rotifer diversity of the wetland is continuing, this interim report raises the total tally of Rotifera known from Meghalaya to 141 species belonging to 41 genera and 20 families.

Phytoplankton communities of Utra and Waithou pats (floodplain lakes) of Manipur, studied during November 2002 - October 2004, revealed 62 and 61 species, and indicated monthly richness between 27-45 (38 � plus or minus 4) and 32-46 (39 � plus or minus 4) species respectively with distinct qualitative importance of Chlorophyta (29 � plus or minus 4 and 28 � plus or minus 3 species). Phytoplankton (154 � plus or minus 31 n/l and 164 � plus or minus 34 n/l) comprised between 43.8 � plus or minus 3.0 % and 41.5 � plus or minus 3.0 % of net plankton abundance respectively of these two lakes. Chlorophyta (115 � plus or minus 23 n/l and 113 � plus or minus 21 n/l), the dominant quantitative component (74.4 � plus or minus 4.1% and 67.5 � plus or minus 4.8%), indicated importance of the demids. Bacillariophyta (33 � plus or minus 9 n/l and 37 � plus or minus 12 n/l) formed sub-dominant group, and Dinophyta > Euglenophyta > Chrysophyta showed very low densities. Various abiotic factors registered relatively limited influence on richness and abundance of phytoplankton as well as on abundance of individual groups in Utra Pat than in Waithou Pat. Multiple regression depicted higher cumulative influence of fifteen abiotic factors on the stated biotic parameters in these pats. Both richness and abundance of Phytoplankton recorded significant monthly variations, showed insignificant temporal variations between two lakes and followed indefinite annual patterns in each pat. Phytoplankton communities of the sampled pats are characterized by higher species diversity, higher evenness and lower dominance.

Plankton samples collected from two sampling stations of Deepor Beel (a Ramsar site in Assam, northeastern India) between November 2002 and October 2003, reveal 110 and 100 species of Rotifera, exhibit monthly richness ranging between 43-65 (56 plus or minus 6) and 38-60 (52 plus or minus 7) species and record 48.9-88.1 and 53.1-89.7% community similarities respectively. Rotifera (231 plus or minus 60 and 198 plus or minus 70 n/l) comprise between 48.7 plus or minus 6.1 and 42.6 plus or minus 4.1% of zooplankton abundance at station I and II respectively, and follow trimodal annual patterns with peaks during winter. Brachionidae (90 plus or minus 43, 79 plus or minus 39 n/l) > Lecanidae (45 plus or minus 13, 29 plus or minus 9 n/l) form important quantitative components of Rotifera while Asplanchnidae > Synchaetidae > Trochosphaeridae are other notable families. Lecane > Brachionus > Keratella > Asplanchna > Platyias contribute notably to temporal variations of the rotifers. Asplanchna priodonta, Keratella cochlearis, Platyias quadricornis, Lecane leontina, Polyarthra vulgaris, Keratella tropica and Brachionus falcatus are important species. Analysis of variance comparisons indicate significant temporal variations in richness and abundance of Rotifera between stations and months. The rotifer communities exhibit higher species diversity, higher evenness, lower dominance and lack of quantitative dominance of any individual species. The present results show no definite periodicity of richness and abundance of this group, families or species. Individual abiotic factors register limited influence on richness and abundance while multiple regression exhibits higher cumulative influence of ten abiotic factors on these parameters at both sampling stations.

Microcrustacea of Loktak Lake (collected during Nov. 2002-Oct. 2004) reveal 57 species and show qualitative dominance of Cladocera (51 species). They indicate monthly richness ranging between 33�plus or minus 6 and 32� plus or minus 6 species, record 51.7-82.3 and 53.6-90.0% community similarities during two years respectively, and follow trimodal annual patterns with peaks during winter. The microcrustaceans (112� plus or minus 17 and 124� plus or minus 13 n/l) form an important quantitative component (45.7� plus or minus 4.9 and 43.3� plus or minus 3.7 %) of zooplankton and show broadly trimodal annual patterns with peak abundance during winter. Cladocera > Copepoda mainly contribute to their quantitative variations. ANOVA registers significant monthly variations of microcrustacea richness and significant annual and monthly variations of their abundance. Richness is positively correlated with dissolved oxygen and is negatively correlated with rainfall, hardness, chloride and total dissolved solids while abundance is negatively correlated with pH only. Multiple regressions indicate higher cumulative effect of 15 abiotic factors on richness and abundance. Our results indicate no definite periodicity of richness and abundance of microcrustacea or their constituent groups during two annual cycles and are characterized by their higher species diversity, higher evenness and lower dominance.

Phytoplankton communities of Loktak Lake (a Ramsar site), studied during November 2002-October 2004, reveal the occurrence of 75 and 71 species, indicate monthly richness ranging between 47� plus or minus 6 and 49� plus or minus 3 species and record 50.0-83.2 and 64.5-84.0 % community similarities during two annual cycles respectively. Chlorophyta (33� plus or minus 5 and 35� plus or minus 5 species) show qualitative dominance and importance of Closterium > Cosmarium > Staurastrum > Micrasterias > Gonatozygon species. Phytoplankton (206� plus or minus 58 and 220� plus or minus 53 n/l) comprise between 45.1� plus or minus 6.5 and 42.9� plus or minus 5.8 % of net plankton abundance, indicate trimodal annual patterns and record peak abundance during winter. Chlorophyta (111� plus or minus 20 and 119� plus or minus 15 n/l), the dominant quantitative component, indicate winter peaks; Closterium > Staurastrum > Gonatozygon > Micrasterias species contribute significantly to their abundance. Ceratium hirudinella (43� plus or minus 52 and 39� plus or minus 37 n/l) is the sole important individual species of phytoplankton. Dinophyta > Bacillariophyta are sub-dominant groups and Euglenophyta > Cyanophyta > Chrysophyta show very low densities. Phytoplankton communities are characterized by higher species diversity, higher evenness and lower dominance. Abiotic factors register limited influence on richness and abundance of phytoplankton and on abundance of constituent groups. Multiple regression indicates relatively lower influence of fifteen abiotic factors on richness of phytoplankton and higher cumulative influence on abundance of phytoplankton, Chlorophyta, Dinophyta and Bacillariophyta.

Plankton samples collected from two sampling stations of Deepor Beel, an important floodplain lake of Assam and a Ramsar site of India, revealed 51 species of Microcrustacea and showed qualitative dominance of Cladocera (45 species). Microcrustacea comprised a significant quantitative component (45.6 � plus or minus 5.8 and 50.8 � plus or minus 4.5 %) of zooplankton and exhibited bimodal and trimodal annual patterns with peaks during winter. Cladocera > Copepoda are important quantitative groups. ANOVA registered significant variation in species richness and abundance of Microcrustacea over time and between stations. Richness and abundance were inversely correlated with water temperature and rainfall, and positively correlated with specific conductivity and dissolved oxygen. Multiple regression registered significantly higher cumulative effects of ten abiotic factors on these two parameters. Our results are characterized by higher species diversity, higher evenness and lower dominance of Microcrustacea and show lack of distinct quantitative importance of individual species.

The rotifer communities of 15 acidic – alkaline and soft – marginally hard water floodplain lakes of the lower Assam valley of the Brahmaputra river basin, characterized by low ionic concentrations, reveal 164 species (178 taxa) belonging to 39 genera and 20 families and represent the richest biodiversity known to date in these ecotones of the Indian subcontinent. Nine species are new to the Indian Rotifera. Cosmopolitan (59.7%) > pantropical (15.2%) > cosmotropical (12.2%) species dominate the taxocoenosis. Biogeographically interesting elements constitute a notable component (13.4%); important members of this category include six Oriental, two Australasian and seven Palaeotropical species. The examined fauna depicts a tropical character with predominance of Lecanespp. (28.0%). Littoral or periphytic rotifers (76.2%) dominate the planktonic species. Rotifers comprise a dominant qualitative (67–103, 79.1 ± 11.0 species) and an important quantitative (mean: 41.1–65.9%) component of zooplankton in all floodplain lakes, register a moderate diversity (mean: 2.036–2.642), low dominance (mean: 0.019–0.216) and high evenness (mean: 0.840–0.893). The examined material indicates several interesting acidophilous elements. Richness depicts significant inverse correlation with pH. Water temperature, conductivity, dissolved oxygen and alkalinity record significant direct relationships with the rotifer abundance. Diversity is influenced by abundance and is also directly correlated with water temperature and conductivity. Canonical analysis shows a notable cumulative impact of six abiotic factors on richness, density and diversity.

Thirty-five species of the family Lecanidae are examined from Tripura state in North-Eastern India. Of these, Lecane levistyla and L. scutata are interesting cold-water forms; L. batillifer is an Australasian element; L. acanthinula and L. sinuata are Oriental endemics and L. braumi, L. lateralis and L. simonneae are palaeotropical species. The lecanid fauna also includes the pantropical L. thienemanni and L. sola while the remainder are cosmopolitan and tropicopolitan elements.

Nine species and subspecies of the genus Testudinella are reported from North-Eastern India. Of these, six are new to India and eight to the North-Eastern region. Remarks are made on their distribution.

One hundred and sixteen species of Rotifera are recorded from seven floodplain lakes of the Brahmaputra basin (northeastern India), the highest rotifer biodiversity recorded from these biotopes in the Indian subcontinent to date. The Australasian Brachionus dichotomus reductus and Lecane batillifer; the Oriental Keratella edmondsoni, Lecane blachei and L. acanthinula; the Palaeotropical Lecane braumi, L. lateralis, L. unguitata, Trichocerca tropis, Testudinella greeni and T. brevicaudata; the Pantropical Brachionus donneri and a rather widely distributed Horaella brehmi represent taxa of biogeographical interest. Three species are new additions to the Indian rotifer fauna and eight are new to the N.E. region. Lecanidae > Brachionidae = Colurellidae > Trichocercidae > Testudinellidae comprise the largest fraction (68.0%) of the examined fauna. Comments are made on the general nature and composition of the rotifer taxocoenosis as well as on acidophilic elements, ecology of various taxa and on the species richness of different lakes.

Thirty-one species of Brachionids (Eurotatoria: Brachionidae) are reported from India. Brachionus bennini (Leissling) and B. patulus macracanthus (Daday) are new records from this country. Two new synonyms are proposed. Comments are made on the distribution of the different taxa.

Among 35 eurotatorian species presently reported from Panjab State, India, ten species are new records to this region while eight are new records from N. W. India. A new synonym is proposed and biogeographical remarks are made.

Ten species of Lepadella Bory de St. Vincent, 1826, including one new species and one new form, are documented from North-Eastern India. Two of these species are new records from this country and six are new reports from N.E. region. Comments are also made on the status and distribution of various Indian taxa.