the (^o/o<<?'s 0/ Tealia crassicornis. 619 



showed no cluinge. A reverse result has been obtained in the 

 case o£ two lightly pii^-mented 7ea^<V^, of the shore-fcype, tak(3ii 

 in 25 fms. near the Eddystone Light, and kindly sent me by 

 the courtesy of the Director of the Plymouth Laboratory. 

 These specimens were kept in faiily strong dayliglit, in a 

 good circulation, and in the course of two months showed 

 a marked increase in the intensity of their pigmentation. 



In deep water off the Cambraes very large TeaJkc are 

 obtained, some of which show a distinct and beautiful 

 lavender shade in all parts of the animal. Tiiis peculiar 

 shade disappears entirely in a few weeks if the S[)ecimen 

 possessing it is exposed to experimental tidal conditions 

 (about 5 hours dry in each 24 hours), but remains fairly 

 constant in those possessing it if they are kept continually 

 submerged in well-aerated water. This seems to be a 

 colour-character occurring only in a small percentage of 

 the deep-water specimens. 



Summary* 



(1) A comparison of various characters, physiological and 

 structural, shows that the shore, deep-water, and intermediate 

 forms of Tealia are adaptational varieties of one species, 

 crassicornis. 



(2) The intricate colour-scheme of the disc and tentacles is 

 a camouflage of great aggressive value, with evidence of 

 warning coloration in some forms. The body-colouring is 

 obliterative. 



(3) The occurrence of strong pigmentation (functioning as 

 a light-screen) in littoral forms grading to the pellucid nature 

 of deep-water forms suggests a relation between intensity of 

 light and depth of pigment, which is confirmed by ex- 

 periment. 



(4) The prevalence of red in deep-water forms is dependent 

 on the twilight conditions obtaining in depths of over 30 fms. 

 in this latitude. 



(5) Some deep-water Tealice have a distinctive lavender 

 shade, probably due to a definite pigment. 



Part 11. — Chemical. By John Smith Sharpe. 



In continuation of the previous work on Actinia, the shore 

 and deep-water varieties of Tealia crassicornis were investi- 

 gated. By contrasting these it may be possible to throw 

 tuither light on the physiological action of the pigments. 



40* 



