476 THE BIOLOGY OF MARINE ANIMALS 



During the summer spawning period, male and female lumpsuckers 

 Cyclopterus lumpus mobilize astaxanthin from the liver, and deposit it in 

 the skin and flesh ; in the killifish Fundulus parvipinnis the female transfers 

 xanthophyll to the ripening eggs, and the sexually mature male increases 

 the xanthophyll content of its skin (la, lb, 2, 33). 



A general tendency has been noted among marine animals to accumulate 

 xanthophylls rather than carotenes. Thus in the numerically important 

 groups of molluscs, crustaceans and teleosts, xanthophylls are the predomi- 

 nant or exclusive carotenoid pigments present. Certain prominent excep- 

 tions are asteroids and polychaetes among which carotene predominates. 

 Carotenoid pigments are widely distributed in the tissues of different 

 animals. A pronounced trend is noticeable for deposition of carotenoids in 

 the gonads, and in many forms they are responsible for the coloration of 

 the integument. 



Pyrrols. Pyrrolic pigments are universely distributed and indeed are 

 essential for life, since the tetrapyrrol nucleus is the basis of the chlorophyll 

 molecule and of intracellular respiratory enzymes. The tetrapyrrol struc- 

 ture is found in the porphyrins, which in specific compounds bear a 

 metallic radicle, magnesium in chlorophyll, and iron in haem and haema- 

 tin. The iron porphyrins or haems, in association with proteins, form the 

 respiratory pigments haemoglobin and chlorocruorin (38, 52, 58). 



No animals above the Protozoa manufacture chlorophyll, and when 

 this pigment is present it is exogenous in origin or is contained in symbiotic 

 algae. Algal symbionts occur in sponges, coelenterates, turbellarians and 

 certain other animals, and carry on photosynthesis within the tissues of 

 their hosts (see Chapter 14). 



Some animals contain green pigments showing affinity to chlorophyll. 

 Phaeophorbides are found in midgut cells of certain polychaetes (Owenia, 

 Chaetopterus), in sufficient concentration to give these organs a greenish 

 colour (Figs. 11.2, 13.2) (10a, 44). Berkeley (3) considered that the green 

 pigment of Chaetopterus is localized in symbiotic or parasitic flagellates 

 living in the intestinal cells of the worm. The echiuroid worm Bonellia 

 viridis is bright green in colour and contains a pigment known as bonellin. 

 In the female the pigment is located in the skin, and in the degenerate male 

 in wandering cells which partially fill the reduced body cavity. Bonellin 

 appears to be a mesochlorin, a substance having a porphyrin skeleton and 

 an opened isocyclic nucleus. The green pigments of other echiuroids 

 (Thalassema, Hamingia) appear to be the same as bonellin. 



Various green pigments, poorly understood, are reported in other anne- 

 lids. Phyllodocin is a green substance responsible for the bright green 

 coloration of the polychaete Phyllodoce. It occurs in the animal in granular 

 form. The green pigment of Eulalia viridis (another phyllodocid) is not 

 identical with phyllodocin. It is apparently mixed with a yellow pigment, 

 but occurs alone in the eggs of this worm. These green pigments are tenta- 

 tively grouped with bile pigments (linear-chain tetrapyrrols) and porphyrins 

 (closed-ring tetrapyrrols) (50). 



