Etude comparative des acides amines de quelques siphonophores

1. 1. Siphonophores—Physonectes— Nanomia bijuga (Delle Chiaje 1841) Agalma elegans (Sars 1846) Halistemma rubrum (Vogt) 1852), Forskalia contorta M. Edw. 1841, Forskalia edwardsi Kolliker 1853 and Calycophores Hippopodius hippopus Forskal 1776 and Rosacea cymbiformis (Della Chiaje 1842) have been studied from the point of view of their free and proteic amino acid composition. 2. 2. The organisms studied were caught by divers, then freeze-dried and analysed by a Beckman Spinco 120 C amino-acid analyser. 3. 3. In the Siphonophores analysed the free amino acid values are extremeley high, between 11.1 and 44.7 per cent of total amino acid. 4. 4. The highest values were found in the most primitive organisms and reciprocally the lowest in the most highly evolved organisms. 5. 5. The whole group may be contrasted with the Medusae Acalephae, in which the free amino acids do not exceed 2 per cent. These observations are followed by remarks on the ecology, flotation, physiology and phylogeny of Siphonophores.