64 CHAETODERMA CALIFORNICA. 



shows through the transUicent body wall. An orange-brown substance incrusts 

 the spines about the cloacal opening. The spicules are represented (Plate 37, 



fig. 19). 



The form of the buccal plate and the position of the mouth opening are 

 shown (Plate 4, fig. 10). The adjacent section of the digestive tube rapidly as- 

 sumes a circular form in section, and a few compact groups of gland cells become 

 applied to the dorsal, and to a less extent the lateral walls. Immediately behind 

 the brain these lobules become larger (Plate 30, fig. 3), but soon disappear more 

 posteriorly. The radula was cut obliquely and it is therefore somewhat difficult 

 to determine its exact relations. The tooth appears to be relatively slender, 

 but its supports and musculature are typical. Behind the radula the pharynx 

 again becomes circular and in this form joins the stomach (Plate 29, fig. 9). 

 This last named organ is at first thin walled, but the epithelium soon grows 

 higher, becomes folded and soon smooths out at the level of the posterior end 

 of the prothorax (Plate 29, fig. 11). Again becoming thick walled and of small 

 calibre it unites with the liver and intestine. From this point onward these 

 last mentioned organs are of the usual type. 



The pericardial cavity is of more than average size (Plate 29, fig. 10) and 

 the heart is highly muscular; otherwise neither these organs nor the connecting 

 sinuses are unusual. 



The specimen is sexually mature and multitudes of sperms have made their 

 way from the gonad through wide tubes into the pericardium and the proximal 

 portion of the coelomoducts. The openings of these latter organs into the peri- 

 cardial cavity are comparatively large and the ducts themselves are relatively 

 simple. As in some other small species the glandular portion is a simple canal 

 extending as far forward as the posterior end of the gonad where it bends 

 abruptly and making its way posteriorly opens by an inconspicuous pore into 

 the cloacal chamber. 



The nervous system is distinct and sharply defined and has been carefully 

 examined, but it does not differ in any important respect from that of C. erudita 

 for example. 



Chaetoderma calif ornica, sp. nov. 



One specimen was collected in the neighborhood of San Diego, California, 

 (Sta. 4381) at a depth of 618-667 fathoms. It measures 24 mm. in length by 

 1.6 mm., the average thickness of the metathorax, and 2 mm. the average diame- 

 ter of the preabdomen. The general appearance of the animal and the relative 

 length of the various divisions of the body are shown (Plate 4, fig. 6). The color 



