6c 



EISEN 



posteriorly emarginated brain and in not possessing any diverticles of 

 the spermathecae. This species is not among those collected by the 

 Harriman Expedition, at least none of those examined by me possessed 

 these characters. 



The above definition had already been made out when I received 

 the admirable description of the species by Professor Moore (Proc. 

 Philadelphia Acad. Sci., 1899). This description is so full that few 

 details need be added. 



Fig. 32. MesenchytrcEiis solifiigus. 



Color. — The object of the deep color is probably not alone to 

 absorb heat, but also to exclude light. The worm breeds under the 

 exposure to constant daylight, and the pigment must admirably serve 

 the purpose of modifying this light. All other Enchytrieidaj can hide 

 themselves under opaque substances, but this ice worm has no place 

 to hide, as the snow and ice are comparatively transparent. The pig- 

 ment is distributed not only in the body-wall, but in most of the in- 

 terior organs, even in the ganglia and the brain. 



