the Coloration of Crustaceans. 14.'i 



observed at St.-Vaast-la-Hougue. In tliis lobster tlieabsenceof 

 pigment did not extend to the eyes, which had preserved their 

 ordinary colour. This phenomenon is not confined to the 

 lobster, but seems to be even of very frequent occurrence in 

 other crustaceans, such as the common edible crab {Cancer 

 pagurus) *, in which I iiave met with very numerous examples 

 of it in the young individuals living beneath the stones of the 

 old oyster-beds near the Isle of Tatihou. 



This more or less complete absence of pigment seems to be 

 related to the nature of the habitat of tliese animals ; the 

 fossorial crustaceans, such as Gebia, Ax'ia, and CalUanassa, 

 are almost entirely white, and the greater portion of those 

 which live in grottos or crannies of rocks likewise assume 

 similar tints. In the lobster especially considerable diflfe- 

 rences of hue have been observed by Mr. E. Lovett f in the 

 neighbourhood of the Channel Islands ; he has described one 

 specimen in particular, which was " of a pale lavender," with 

 a mauve [)atch on thecephalotliorax, and the chelai of a brigiit 

 pale blue. This lobster, which had been sent to him alive by 

 M. Sinel, of Jersey, was still living when he examined it: it 

 was a female with eggs. Mr. Lovett also mentions other 

 colours in the lobster — white spotted with blue, " dappled 

 blue and grey," uniform grey, and finally a curious variety of 

 a ])ale reddish colour with the antennie " of a decided bright 

 red." It was maintained at a certain period by Bell that the 

 variations in colour are purely local, each race of lobster thus 

 having a peculiar facies, so much so that a Jersey lobster 

 would be distinguished at once from a French one ; the fact 

 in itself is certainly true, but only arises from the different 

 conditions of medium which the animals meet with at diffe- 

 rent ])laces. As is remarked by Lovett, the coloration must 

 be related to the depth of the water, which allows more or less 

 light to penetrate, and also to the number of the grottos and 

 natural crannies, which, as we know, are very numerous at 

 certain points of the coast of the Channel Islands, as, for 

 instance, in Sark. 



I therefore think that these cases of pseudo-albinism in 

 lobsters, such as that of the roseate specimen of JMr. Lovett, 

 the greenish -white individual which has been reported to us 

 by M. Martin, and finally the one which M. Bietrix has told 

 us is under observation at Concarneau, are only normal indi- 

 viduals which have lost their pigment of the cyanic series as 



• Ca.<es of nielanifsm in the same species, due to itijurv to the derm, 

 are also met with ; the crab becomes entirely blacky or " charbonn^ " as 

 the Fivuch sailors say. 



t * Zitulogist,' ser. o, vol. viii,, 1884, \). JOl ; and my. o, vul. i.\., ISH'J, 

 !>. 10:.'. 



