1897] NOTES AND COMMENTS 9 



draws his supply from the insect's mouth, especially when she dis- 

 gorges to feed a comrade. A mite carried on the abdomen of an 

 ant taps, with his two front pairs of feet, another ant which happens 

 to be near, and for thus asking obtains food. No benefit to the ants 

 from the presence of these mites is suggested, and the relation bears 

 the aspect of disinterested charity. 



Another species of mite, Discopoma comata, is on the other hand a 

 true parasite. These gamasids attach themselves to the ant's ab- 

 domen, pierce the intersegmental membrane, and suck food-supplies. 



A bristle-tail or thysanure, Lepismina polypoda, plays the part of 

 pickpocket in the ant-colony. He comes stealthily between two 

 ants when one is feeding the other, grabs the drop of liquid nourish- 

 ment in its passage, and makes his escape as quickly as possible to 

 levy contribution on other couples until his hunger is satisfied. 



The Pigments of the Decapod Crustacea 



Another interesting contribution has just been made to our know- 

 ledge of the pigments of the decapod Crustacea by Miss M. I. 

 Newbigin (Journ. Physiol, vol. xxi., pp. 237-257, May 1897). 

 She discusses the predominant characteristics of the pigments of 

 Homarus vulgaris, Nephrons norivegicus and Astacus nobilis. The 

 conclusions arrived at support recent observations on the same sub- 

 ject, but a speculative tone mainly towards the end of the paper 

 rather spoils the general effect. 



Thus we cannot accept the conclusion "that there is some con- 

 nection between the little known substance in the muscle and the 

 formation alike of the blue pigment and of chitin." The conclu- 

 sion also that the red lipochrome is present as a calcium combina- 

 tion in the shell is only speculation. The pigment is laid down 

 there before calcification takes place : in fact pigment and calcium 

 salt are more or less independent of each other. 



While in the earlier parts of the paper a distinction is drawn 

 between the yellow and red pigments, in the ' summary ' the former 

 is said to be partially derived from the latter " under the influence 

 of certain reagents." A ' lipochromogen ' is not a ' compound ' of 

 a lipochrome : it is a precursor of one. The return to Krukenberg's 

 term ' hepatochrome ' would certainly be unfortunate, as the organ 

 in which such pigment or rather pigments occur is not a liver but 

 mainly a pancreas, and although no band in red was recognised in 

 extracts of the digestive gland by Miss Newbigin there is a chloro- 

 phylloid pigment, which is better named enterochlorophyll, present 

 in most if not in all cases. 



There is no mention of this spectrum given by the pigment itself 



