618 Messrs. K. Elmhirst and J. Smith Sliarpe on 



surface of this species are, they may be grouped more or les 

 as follows : — 



Type 1. Colours complementary. 



Type 2. E-ed of the primary disc-bands outstanding. 



Type 3. Uniform sombre tint. 



Type 4. Disc as any of the above associated with white 

 tentacles. 



Tealice in captivity are usually expanded at night, and I 

 can confirm the observations of Fleure and Walton that they 

 react to strong light by closing, which surely indicates that 

 the pigmentation of the oral surface is adapted for use in 

 weak light, whilst the denser pigmentation of the body-wall 

 serves in strong light. 



The lighter lipochrome pigmentation, brighter colours, and 

 almost continual exposure of the oral surface of cave-dwelling 

 and sublittoral specimens living in less brilliant light-con- 

 ditions illustrates the reduction of pigment in reduced light, 

 which is still further confirmed by the delicate colouring, 

 absence of heavy lipochromes, and pellucid nature of speci- 

 mens from depths of 30 fms. and more. The abundance of 

 lipochromes, presumably with the power of producing active 

 oxygen, in shore-forms and the comparative absence of them 

 in specimens from totally submerged habitat, suggests a pro- 

 vision for some respiratory requirement during ebb in the 

 former, which is not necessary to the latter. 



Experimental. — When Tealice are kept in captivity they 

 often lose much of their natural brightness and delicacy of 

 colouring — as has been noted in the case of other species ; in 

 such changes the general tendency is towards the assumption 

 of a uniform sombre tint, such as is found locally in some 

 shore Tealice. Deep-water Tealice also w4ien kept in strong- 

 light lose brilliance and assume a more or less uniform brick- 

 red shade. To test the relation between pigmentation and 

 daylight, some shore Tealice were kept in complete darkness 

 for six months in a tank with a good water-supply (well 

 aerated and plankton available as food, nioie solid food being 

 given fortnightly). At the end of the experiment, the pig- 

 mentation of the column, disc, and tentacles was found to 

 have markedly decreased. The disappearance of pigment 

 was most marked in the lower part of the column, and least 

 marked in the tentacles. A rich red deep-water Tealia in 

 the same experiment paled noticeably, except in the oral 

 surface, and tended to assume a dull olivaceous shade from 

 below upwards. In Actinia^ similarly, paling took place ; in 

 Adinoloha both orange and white varieties were tried, but 



