Coluratioit of Marine Aniiuafs. 229 



'J'lic mollification of the natural hue is tliiis considnrablc. 

 Yet l/i/as uranetat far surpa.ssi's it in the number and variety 

 of its parasitic growth.s, thatof youn^ spccimen.s from cavern- 

 roofs resenihlint^ the dorsum of A/>hro(lita. As the line of this 

 species is brownish ])urple or reddish purple, it might be 

 supposed that the extraneous growths would be protective. 

 Ilyas courctatus is even more subject to such growths, yet 

 both, covered with parasites as they are, abound in tiie 

 stomach of the cod, which pays scant attention to coloration. 

 Jlippolyte in the rock-pools of St. Andrews often differs from 

 the tints of tiie seaweeds it frequents. Again, why should 

 the female Pinnotheres in the horse-mussel be so brightly 

 coloured, the male being less conspicuously so ? Both are 

 equally protected. Many pelagic crustaceans are also more or 

 less translucent. Mysis jiexuosa is grey wlien on sand, brown 

 or green wlien amongst seaweetl of these two colours. The 

 gribble, whose sole function is to perforate wood, and thus is 

 constantly sheltered, is more soberly tinted than, for instance, 

 other Isopods, such as Splueroma in fissures of rocks, which 

 has its under surface speckled with white, legs with brown, 

 and head with brown, white, and red. Uyperia galha in the 

 gastric cavities of Aurtlia aurita is often reddish brown. 

 Brightly coloured crustaceans like Dexamine spinosa are eaten 

 by fishes. The pelagic Zoece have conspicuous greenish-blue 

 eyes, and the pelagic young of Crangon are brightly tinted. 

 Cap7-eUa tuberculata, again, occurs in swarms on Ceramiuni 

 rttbrum, and is of the same tint. Idotea pelagica on Ceramiuni 

 rubrum is sometimes beautifully speckled with white in 

 marginal scallops or central streaks, and is thus more con- 

 spicuous than usual. Fodocerus pulchellus frequents the 

 same seaweed, with which it harmonizes in colour j but here, 

 again, it is sometimes gaudily tinted with reddish brown aud 

 white, so as to be conspicuous. I^lany sessile- eyed crusta- 

 ceans are beautitully tinted, like Muntagua vwnoculotdcSy with 

 reddish-orange or orange specks in rows on the dorsum, and 

 others are nuirblcd with brown and white. The pelagic 

 Eurydice pulchra and Janira maculosa of our seas are not 

 inconspicuous in coloration. 



On the other hand, many land-crabs, such as Ocypoda^ as 

 Prof. Moseley tells us, are tinted ot a bright red or other 

 conspicuous hue. The reddish Morway lobster frequents 

 greyish mud, from which the cod picks it up so readily. 

 The comnjon shore-crab is often variegated with white in the 

 brackish inlets of the Outer Hebrides. The reddish-orange 

 Aljilieus ruber is as consjjicuous as it can be in the tidal pools 

 ot lleiii). The multitutles of the sand-hoppers are white and 



