CHAPTER VII 



FRESH WATER ANIMALS : DEPOSITS : AMPHIBIA 



INVERTEBRATES 



Information on the carotenoid distribution in the lower forms of 

 fresh water life is meagre. Some fresh water Crustacea are very similar 

 to marine Crustacea in containing astaxanthin, e.g., Gammarus pulex,'^ 

 Daphnia longostra and Cyclops species. ^ Crystalline astacin (the 

 oxidative artefact of the naturally-occurring astaxanthin) has been 

 obtained from the crayfish {Potamohious astacus). Others, however, do 

 not contain this carotenoid, for Daphnia magna contains only hydro- 

 carbon carotenoids^ and Asellus aquaticus only (3-carotene and crypto- 

 xanthin. * In mixed samples of zooplankton containing 85 per cent, of 

 D. longostra and the rest Cyclops, astaxanthin is by far the predominating 

 pigment, the amounts of astaxanthin, other xanthophylls, and carotenes 

 being respectively 6-52 mg., 1-38 mg. and 0-12 mg. per g. dry weight. ^ 



The caverniculus amphipods Niphargus (Sygodytes) spp. contain 

 no carotenes, but their eggs are reported to be pink, ^a 



Helix pomatia, according to the very old work of Kruckenberg and 

 of McMunn, possesses a hepatic carotenoid^, probably a mixture of 

 alimentary origin, as does another unspecified snail.' Seybold and 

 Egle' state that, compared with its food, the edible snail excretes 

 faeces containing relatively more carotenes than xanthophylls. Their 

 claim that this indicates preferential destruction of the xanthophylls 

 by the gastric secretion of the snail, must be accepted only with 

 reservation. 



Cain " has recently provided histochemical evidence that carotenoids 

 accumulate in the interna of the Golgi apparatus of the neurones of 

 Helix aspersa, Planorbis corneus, and Limnaea stagnalis. The accumula- 

 tion is greatest in the two last-named species. 



Recently Comfort® has examined the highly-coloured egg mass of 

 the South American gastropod Pila canaliculata* The pigmentation 

 is due to a carotenoid protein complex very similar to those commonly 

 found in marine crustacean eggs. On denaturation of the complex a 

 mixture of a number of carotenoids, mainly hypophasic in a 90 per cent. 



* In his paper, Comfort describes his material as P. glauca but in a private 

 communication to the author he states that it is more probably P. canaliculata. 



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