6 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY. 



complete want of colour and by an allied transparency. The burrow- 

 ing prawns (Callianassa, Gebia and Axius) on the other hand, 

 are characterised by porcelain-like shell armour, ' either of pearly 

 whiteness or else of coral pink. 



III. Albinism among Marine Animals. 



From the preceding note, the transition is natural to a con- 

 sideration of albinism generally among the inhabitants of the sea. 



At the outset we may well consider the characteristics of 

 albinism among land vertebrates. There the phenomenon is seldom 

 found among the Reptilia. It is among the divisions possessing 

 feathery and hairy epidermal clothing (Aves and Mammalia) that 

 it is met with most frequently. Lack of colouring matter in such 

 cases, means albinism of snowy whiteness of plumage or pelt, i.e., 

 opaque whiteness. As every one now knows, when such is not an 

 abnormal feature but is the settled hue during life or is regularly 

 recurrent at one season, the possessing animals are, in a great 

 majority of cases, inhabitants of snow-bound regions — polar or else 

 above the snow-line in our great mountain ranges. 



Albinism here may be assumed either as a method of protection 

 or as a device to allow of unobserved stalking by carnivorous animals. 



In the sea albinism in this narrow sense of opaque whiteness is 

 seldom met with. There are no snowy plains beneath the waves — 

 indeed in the dim light that reigns in the shallows and in moderate 

 depths, whiteness would be a positive and very dangerous attribute. 

 To the weak and ill-armed it would mean speedy extermination — 

 so where it is present, either its employment will fall into the 

 category of (a)- warning devices, (b) lure devices to attract prey, 

 or lastly (c) where the possessor has neither use nor fear for any 

 particular colour. 



It may here be convenient to place in tabular form the more 

 common albino representatives yielded in British Seas by the various 

 animal classes. 

 Protozoa : — Foraminifera, e.g., the porcelain-white tests of Mili- 



olina, &c. (calcareous). 

 SPONGIDA : — a. The aspiculous Halisarca sometimes. 



b. The calcareous sponges generally, e.g.. Leucandra 

 nivea, Ascaltis, Sycandra ciliata, 8. compressa 

 and often Ascetta (Leucosolenia) coriacea. 

 Cnidaria : — Actinoloba dianthus ; Alcyonium digitatum. 

 Vermes :— Turbellaria, several. 



Polychseta, Nephthys (burrowing), and the white plumes 

 of a certain Sabella, 



