126 bulletin: museum of compakative zoology. 



circular layers. Of the latter the outer ch-cular muscles remain very 

 thin throughout the hody, while the inner become massively devel- 

 oped in the nephridial region, back of which they terminate abruptly, 

 except for a few delicate fibers which continue to the ])Osterior end 

 of the body. The longitudinal muscles are highly developed through- 

 out the body. A very massive layer of longitudinal muscles lies 

 between the proboscis sheath and intestinal canal. These muscles 

 are thickest immediately behind the ne|)hridia, and join the main 

 longitudinal muscular layer ])osteriorly to the end of proboscis 

 sheath. Proboscis sheath extends through about half the length of 

 the body. Proboscis composed of two muscular layers — • an inner 

 circular and an outer longitudinal layer — outside or between which 

 is a firm basement membrane or layer of connective tissue. Pro- 

 boscis cavity separated into three chambers, of which the anterior 

 is bulb-like in some states of contraction and resembles the middle 

 chamber of the proboscis of some of the Hoplonemerteans, although 

 it is without armature. 



Nephridia much as in Carinella linearis. Blood vascular system 

 consists of very large cephalic lacunae and a jiair of large lateral 

 vessels. These latter lie internal to the inner circular layer in the 

 esophageal region ; farther back they pass outside this layer and lie 

 between it and the longitudinal muscles, while in the intestinal 

 region they become imbedded in the longitudinal muscles. 



Brain shaped much as in Carinella and similarly situated 

 immediately beneath the basement layer of the integument. Lateral 

 nerves likewise situated between the outer circular muscles and the 

 basement meml)rane, although in the nephridial region, and through- 

 out all the body more posteriorly, the nerves sink inward among the 

 longitudinal muscles, carrying at least a portion of the very thin cir- 

 cular layer with them. By this means the nerve cords may come to 

 lie well toward the inner border of the longitudinal muscles (PI. 9, 

 fig. 60), although still situated to some extent outside the very thin 

 layer of circular muscles. 



Sexual glands develop as small pouches lying in the longitudinal 

 muscles on the dorsal side of the body. 



This new genus is of especial interest in that it unites many of the 

 characters of Carinoma with others that have been considered 

 pecuhar to the Carinellidae. The genus Carinomella furnishes a 

 strong argument in support of Bergendal's recent contention (:00) that 



