CHAETODERMA VADORUM. 195 



with walls of the usual character, pursues its course to the end of the preabdomen 

 where it becomes unusually narrow and contorted before opening in the cus- 

 tomary fashion into the cloacal chamber. Food products, among them rela- 

 tively long and slender tubular fragments of some unknown organism, are 

 present in considerable quantities in the stomach and the proximal part of the 

 hepato-pancreas and in a more or less digested condition throughout the intes- 

 tine. 



So far as could be determined the circulatory system is typical of the genus. 

 As noted in connection with the reproductive system the aorta at its origin is 

 unusually heavy walled and of large cahbre. In the region of the gonad its 

 walls become thinner yet distinct so that they may be traced readily to the 

 neighborhood of the radula where it disappears as a distinct vessel. 



The nervous system is very distinct and has been examined with more 

 than usual care, but in all essential respects it is practically the same as in 

 C. attenuata for example. 



The single specimen sectioned is a female with the sex gland, filled with ova 

 in all stages of development, holding the customary position. At the junction 

 of the preabdomen with the tail-hke postabdomen the ovary rapidly narrows 

 to form the paired canals leading into the pericardium. These, however, are 

 of unusual extent, traversing almost the entire extent of the postabdomen, and 

 are separated from each other by the large dorsal aorta (Plate 8, fig. 11) whose 

 walls in this region are relatively heavy. In the neighborhood of the peri- 

 cardial cavity they become somewhat enlarged but otherwise they exhibit no 

 unusual features. 



The pericardium is of moderate size and the coelomoducts open in the 

 usual position (Plate 9, fig. 6) by very distinct, ciliated funnels connected with 

 a short non-glandular section directed anteriorly. At the le\'el of the dorsal 

 commissure they unite with the glandular portion which though it is of large 

 size relatively, lacks the sacculations and tortuous course characteristic of 

 larger species and passes directly backward to open at the usual point in the 

 cloacal chamber. The cells lining this main division of the canals are com- 

 posed of highly vacuolated protoplasm frequently in the process of liberating 

 its products by means of constriction of the distal end of each cell. 



Chaetoderma vadorum, sp. nov. 



One specimen (Plate 13, fig. 1) of this species was taken ofif the south coast 

 of Maine (Sta. 3B) at a depth of 64 fms., another from the same general locality 



