230 Prof. W. C. M'Intosh on the 



easily seen amongst dried sand and seaweeds. The parasitic 



cirripede on whales [Coronula) retains its white colour, and 

 Lepeophtheirtis on the salmon and Caligus on the cod each 

 have their brownish-olive hue and are readily seen on the 

 skin. 



Some pelagic crustaceans (Copepoda) are of a deep blue or 

 brilliant scarlet, and the young pelagic stages of many of the 

 higher Crustacea are marked with vivid tints. The pelagic 

 barnacles are not inconspicuous. Even the translucent 

 Phronhna (Amphipod) has three sets of coiiS])icnous eyes. 

 Prof. Moseley describes the deep-sea shrimj)s and schizopods 

 as of an intense bright scarlet colour. A deep-water SeroliSy 

 again, described by Mr. Beddard is blue. 



There is no evidence that the tints in any of those con- 

 spicuously coloured act as a warning, since they are found in 

 the stomachs of fishes equally with those of sober tint. The 

 diurnal changes of hue in such as Uippolyte are, moreover, 

 not always explained by their envii'onment *. 



The Brachiopods are generally pale, yet Lingula, an 

 ancient type which frequents sand, has its valves tinted of a 

 tine greenish hue. 



Some of the Polyzoa are brightly coloured, e. g. Bugula, 

 which is purple, whereas others, such as GetneUaria, have a 

 uniform ])ale straw-colour. Memhranipora is conspicuous by 

 its pale lacework on the blades of the tangles. The majority 

 of the Polyzoa, e. g. the Leprah'ce, have no vivid coloration, 

 though some are pinkish, and so with Flustra. Their colour 

 does not appear to have any relation to Natural Selection and 

 is neither protective nor warning — not more so than the 

 purple of the alga Corallina officinalis. 



While the adult Fhoronin, which is tubicolar, is either pale 

 or with dark brownish tentacles and pale body, the pelagic 

 young {Actinotrocha) is brightly tinted. Tliis might be 

 explained by supposing that these tints are ancestral and that 

 former conditions may have necessitated tiiem. Such, how- 

 ever, is conjecture, as also is the view that disadvantageous 

 colours in the young have little time to do harm. 



The colours of the next group — that of the shellfishes — 

 have long been a source of interest ; and as they affect both 

 the hard and the soft parts, their study might be supposed to 

 throw some light on the questions before us. 



Comparatively few examples of protective coloration occur 

 amongst the bivalves, the calcareous valves of which, perhaps, 



* Vide on this subject the \aluable paper by Messrs. Gamble aud 

 Keeble, Quart. Journ. Micr. Sc. vol. xliii. pp. 589-61)8, pis. xxxii.-xxxvi. 

 (IIJUO). 



