Coloration of Marine Animils. 23.'!) 



be a warninp; coli)ur, as Mr. Garstaii}2^ su[)|)03e3, for somo 

 fislus eat them. Tlie tadpoles of such forms as Sti/eJa are 

 pink. Chivelinn sliows brip^ht orange and yeUow, and brii^ht 

 green characterizes A. intestinalis in tangle- roots and similar 

 places between tide- marks, and A. depressa under stones in 

 rock-pnols. It the red hue of some Ascidians, e. g. ^. scahra, 

 is assumed to be a warning colour, what is to be said about 

 such as Mof(/iil(i, a colourless form, invested by a thick layer 

 of gravelly mud or sand? 



Is the dull red of Styehi grossniaria, projecting here and 

 there through a layer of Ilalichondria panicea on the roofs of 

 sheltered caverns, in the s.ime category in regard to warning 

 coloration as Ascidia scahra on the floating blades of the 

 tangles? 



The pelagic Appcndicularians and their houses are generally 

 translucent, but some are pinkish. Their vast numbers, 

 however, are little in need of protection. 



The Compound Ascidians, such as Botryllus, Botrylloides, 

 Leptodinuw, and Aplidiuin^ are often strikingly coloured, 

 such as the yellow stars of Botryllus Schhsserij the white 

 surface of LeptocUnum durum, or the cinnabar colour of 

 others; yet this does not appear, so far as observations go, to 

 be either for {protection or warning. Fishes bite off the sea- 

 weeds on which some grow and swallow them. 



Certain Cyclostomes, like Myxine, living in mud are of a 

 flesh tint or purplish, as in Bdellostoma, while the river- 

 lamprey is olive and the marine boldly mottled with bluish 

 grey and black. Myxine has no warning tint, yet its abun- 

 dant mucus is most offensive. 



Amongst Fishes the bony forms (Teleostei) are, on the 

 w hole, the most brightly coloured, the Elasmobranchs being 

 njore soberly tinted. In some bony fishes both sexes are 

 brilliantly coloured, in others only the male. One general 

 rule, with a few exceptions, prevails throughout the series, 

 viz. that the dorsum is dark and the under surface pale, 

 aj)parentl3' for protection, the explanation usually given being 

 that, looked at from above, the dark dorsum renders the fish 

 more or less obscure, whereas looked at from below the white 

 or pale under surface is invisible against the sk}'. Yet 

 Cottun scorpius in rock-pools occasionally has the head pale 

 orange and the dorsum speckled with the same colour, 

 and the skate has a grey under surface. Further, when the 

 under surface is upturned, as in Remora, it becomes dark, 

 but no mention is made of the dorsum, which remains dark. 

 It can hardly be supposed, however, that many species of 

 skate have a white under surface for this purpose, though 



