228 Prof. W. C. M'lntosh on the 



Palolo takes place for its pelagic stage, and the hues of the 

 pelagic phases of the Nereides are likewise vivid. The 

 colours of the pelagic young of the sedentary forms, such as 

 t>thenelais, are often brightly coloured. 



Annelids \vhich perforate hard substances, as Polydora and 

 Dcdccaccria, are coloured equally with the free, and the pelagic 

 phases of the latter retain vivid tints. 



1 he Neraerteaus and other Turbellaria, with a few excep- 

 tions, such as Nemertes carcinophiJa, are often of a colour at 

 variance with their surroundings — and the same may be 

 said of the Leeches ; but the Gephyreans, especially those 

 frequenting mud, are generally inconspicuous, though Bo- 

 nellia is green. Tlie marine Planarian Eurylepta vittata 

 between tide- marks is conspicuously banded with brown and 

 yellow, and others are similarly variegated with red, purple, 

 and yellow. Many, however, are of a uniform colour and 

 otten resemble their surroundings. As anemones and fishes 

 prey on them, their coh)ur would not seem to be protective, 

 either in the sense of corresponding with their environment 

 or acting as a warning to predatory forms. Mr. Punnett tells 

 of a small Nemertean parasitic in an Ascidian which is 

 brightly striped, and larger free species are similarly banded. 

 Borlusia Eh'sabeihce, which is boldly blotched with purplish 

 brown and white, lives in a tube of mud under stones ia 

 Herm. 



The coloration of the sexes in the Crustaceans is often 

 similar, as in the common and the Norway lobsters, though 

 in some {e. g. the shore-crab) there are marked differences. 

 Yet after all what selection can a female shore-crab exercise 

 "when the courting is carried on when she is in a soft and 

 iielpless condition immediately after casting her shell? The 

 minute complemental males of certain Cirripedes afford 

 similar data. 



'i'he evidence in regard to protective coloration is some- 

 what ambiguous. On the one hand, Prof. Moseley states 

 that the Crustaceans {Naatilogropsus) found on the gulf-weed 

 resemble it in tints, even to the white patches which imitate 

 those of Memhraitipora and the sea-acorns [Balani). He 

 also records a similar crab of a blue hue on the float of 

 Janthina. Fortumnus variegatus somewhat resembles the 

 greyish hue of the sand amongst which it lives. The colora- 

 tion of the stalk-eyed crustaceans is often curiously compli- 

 cated by parasitic growths, such as alg£e and zoophytes. 

 Kven the slender Stenorhyuchus rostratus has its dorsum and 

 limbs eidivened by tufts of Ulva or hy Plu miliaria, Campanu- 

 luiia, patches of JJalichondjia, and the tubes of Terebellte. 



