ENCHYTR^ID^ 



33 



The color clue to thick layers of pigment found principally in the 

 longitudinal muscular layer as well as in the membrane lining the 

 coelomic cavity. Color varies w^ith the specimens, some a deep choco- 

 late brown, others yellowish or reddish brown. All have a lighter 

 clitellum. (Alcoholic specimens.) 



Brain (fig. 12^). — The brain is anteriorly deeply emarginated ; it 

 is broad and short. 



Dorsal vessel. — Like the intestine, covered by a thick layer of 

 chloragogen glands of a dark brown color. 



Fig. 12. Mesenckytrceus obscurus. 



SpermatJiecce (figs. \2a and 12c). — The spermathecze, on account 

 of their great length and twisted nature, were not dissected out entire, 

 and the figures are composed from two or three broken pieces and are 

 accordingly not quite so satisfactory as could be desired. But from a 

 comparison with the sectioned specimen it seems that the form is fairly 

 correct as given. The vmusually elongated ampulla extends back to 

 somites IX or X. It is more or less folded, and does not seem to 

 connect with the intestine. The spermathecae are so large that they 

 do not lie abreast, but one is pushed much farther ahead than the other. 

 Thus while one spermatheca had its ampulla strongly folded in somites 

 VI and VII, the other extended to somite X. 



Atrial glands (fig. 13c). — I counted variously 16 to 20 atrial 

 glands. They are grafted on the atrium, surrounding it on all sides, 

 but are more numerous on one side than on the other. They enter 

 the atrium as in M.fuscus., but are not surrovmded by the circularly 

 twisted muscles found in that species. These atrial glands are free in 

 the coelom. Enclosed in the penial bulb we find a number of penial 



