ON COLOURING MATTERS OF VARIOUS ANIMALS. 17 



Antedoiiinj found in certain Holothurians as well as in 

 Antedon. 



Hoplacanthinin . 



Crustaceorubrin. 



Aplysiopurpurin (the same probably in Doris). 



lanthinin. 



No doubt the list is capable of much furthur extension. 

 Besides haemoglobin, the distribution of which is so wide 

 and yet so partial (Lankester, ' Proc. Royal Soc.,' No. 140, 

 1873), and bile pigments, peculiar colouring matters giving 

 absorption spectra have now been found to exist in members 

 of all the seven groups of the animal kingdom. Amongst 

 Protozoa such colouring matters occurs in Infusoria and 

 Sponges ; amongst Coelenterata they occur both in Anthozoa 

 and Hydromedusae, in Echinodermata in both Crinoidea, 

 Echinoidea and Holothuroiclea, but not in the Asteroidea. 

 In Vermes, in Annelids and Gephyreans. In Arthropoda, 

 in Crustacea and in Insecta. In Mollusks, in Gasteropods 

 only. In Vertebrata, in four fish, three species of Odax, 

 and one Labricthys, and twelve birds^ of two closely allied 

 genera. The Echinodermata and Coelenterata appear to be 

 the groups which are most prolific of such colouring matters. 



The apparently capricious restriction of these colour- 

 ing matters to certain parts only of the animals possessing 

 them has been dwelt on by Professor Lankester (/. c). 

 In the case of haemoglobin such instances, as its restric- 

 tion to the pharyngeal muscles of certain Gasteropods, and 

 the nerve-ganglia of Aphrodite aculeata, may be cited, as also 

 its occurrence only in the muscles of the dorsal fin of Hip- 

 pocampus amongst the muscles of that fish. I may add an 

 observation of my own of a somewhat parallel case to this 

 latter, viz. that in sharks of the genus Carcharias, of which 

 many were caught and skinned on board the Challenger, a thin 

 layer of muscles next the skin, and closely adherent to it, 

 is tinged of a deep red colour with haemoglobin, appearing 

 like mammalian muscle, whilst all the deeper layers of 

 muscle forming the main mass of the body are pale and almost 

 white. In a Carcharias brachiurus caught off the Ker- 

 madec Islands this red layer of muscles was not more than 

 a quarter of an inch in thickness. Mr. Lankester accounts 

 for the presence of the haemoglobin in the muscles of the 

 dorsal fin of Hippocampus by the special activity of that 

 organ, but such an explanation fails in the case of the shark, 



^ Duriug the voyage of the Challenger I believe 1 saw a notice iu some 

 scientific periodical to the effect that turaciu had been discovered in an 

 Australian parroquet. I cannot find the statement again. 



VOL. XVII.— NEW SER. B 



