GRISWN PIGMliNT OF INTESTINAL WALL OF CH.15T0PTERUS. 451 



that of the allied Bouellia viridis. It is, however, quite 

 unlike it. In actual tint Th. Laukesteii is of a much 

 brighter green than Bonellia viridis — tending to what is 

 called apple-green, whilst Bouellia is rather to be described as 

 chrome-ureen. Tlie colour of Th. Lankesteri is exactly the 

 same as that of Hamingia arc tic a. I am able to state this 

 as I am, I believe, the only person who has seen and recorded 

 by a coloured drawing this Gephyrsean in a living condition. 

 I dredged it in company with the Rev. Dr. Noiinan, F.R.S., 

 and Professor Bourne, F.R.S., of Madras, at the mouth of 

 Lervik Harbour, Stordoe, Norway, in 1882. Moreover, the 

 green pigment of both Thalassema Lankesteri and Ha- 

 mingia arctica differs from that of Bonellia in that it is 

 not soluble in alcohol.^ According to Professor Herdman's 

 observations, the pigment of Th. Lankesteri is slightly 

 soluble in formol. Whether this signifies more than that the 

 water holding the formaldehyde in solution takes up the 

 pigment, and would do so even were the formaldehyde 

 not present, seems doubtful. I have no observation as to 

 solubility in water in reference to the green pigment of 

 Hamingia, but it appears to me highly probable that it is 

 identical with that of Thalassema Lankesteri. In addition 

 to their want of solubility in alcohol, these two pigments differ 

 from that of Bonellia in not yielding a series of detached 

 absorption bands. I determined this in the case of Ha- 

 mingia, and Professor Herdman has done so for his new Tha- 

 lassema. Thalassemin does not change its colour when acted on 

 by dilute acids, whilst Bonellin is changed to a rich violet tint. 

 A second instance of green tegumentary pigments differing 

 from the Bonellin group is presented by I do tea viridis, the 

 Isopod crustacean. The pigment is in this case insoluble in 

 water, alcohol, or benzine. It is of a brilliant grass-green 

 colour, and is not improbably similar in character and origin 

 to the green pigment situated in the skin of some Lepidopterous 

 larvae, and other adult leaf-frequenting insects. It is time 



^ See Professor Herdinau's paper, aud accompanyiug uotes by Professors 

 Sheniugton and Noel Patou, aud Miss Newbigiu. 



