CHAETODERMA SCABRA. 63 



organ appears to be typical though the glands that open along its margin are 

 more than usually developed. The preradular section of the gut is of average 

 diameter, fairly muscular and is provided with numerous glands uncommonly 

 compact except on the dorsal side behind the brain. Violent contractions of 

 the prothorax have apparently been responsible for the dislodgment of the 

 epithelial lining of this part of the digestive tract; but there are indications that 

 a subradular organ exists and the nerve supply is distinctly evident. The radula 

 is constructed on the usual plan as may be seen (Plate 26, fig. 2). Beyond the 

 radula the gut becomes narrow, circular in section and very soon unites with the 

 capacious stomach whose relations to the intestine and liver are of the u.sual 

 type. The stomach and especially the intestine contain a considerable amount 

 of inorganic and organic material, diatoms being especially abundant. 



The single specimen is a male with the gonad distended with sex products 

 in all stages of development. Violent muscular contractions have forced a mass 

 of sex cells, many of them immature, into the pericardium; and at various points 

 along the coelomoducts fully developed sperms are present. The reno-peri- 

 cardial openings, at the level of the posterior border of the suprarectal commis- 

 sure, are relatively wide and lead into correspondingly spacious, highly ciliated 

 tubes which pass almost directly ventrally to a point about opposite the mid 

 lateral line where they unite with the glandular portion (Plate 36, fig. 1). This 

 last named section extends as a slightly convoluted tube to a point about oppo- 

 site the posterior border of the gonad where it bends sharply upon itself and 

 ventral to the dorsal ciliated section opens into the cloacal chamber at the usual 

 point. 



The nervous system shows with distinctness and has been traced in con- 

 siderable detail, but as the results show it to be essentially the same as in C. 

 attenuata and C. erudita it demands no especial description. The subradular 

 ganglion with the usual connections is clearly a single mass. 



Gland cells in the gills are very definitely distributed, in cross sections being 

 disposed along the transverse axis of the body (Plate 26, fig. 5). 



Chaetoderma scabra, sp. nov. 

 One individual was dredged in Monterey Bay, California at a depth of 

 795-871 fath. It measures 12 mm. in length, 1 mm. through the metathorax 

 and 2 mm. through the greatest diameter of the preabdomen. The expanded 

 portion of the prothorax is light brownish yellow; more posteriority the brown 

 shade is more pronounced, becoming olive-green in the region of the liver which 



