04 CHAETODERMA CALIFORNICA. 



shows through the transhicent Iwdy wall. An orange-brown substance incrusts 

 the spines about the cloacal opening. Tlie s])ifules are rejiresented (Plate 37, 

 fig. 19). 



The form of the buccal plate and the position of the nujuth oj^ening are 

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

 sumes a circular form in section, and a few comi)act groups of gland cells become 

 applied to the dorsal, and to a less extent the lateral walls. Innnediately liehind 

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

 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 tliin walled, but the epithelium soon grows 

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

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

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

 last mentioned organs are of the usual type. 



The ])ericardial cavity is of moi-e 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 matiu'e ami nuiltitudes of sperms have made their 

 way from the gonad through wide tubes into the pericardium and the ]iroximal 

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

 cardial cavity are comjiarativel.y large and the ducts themselves are relatively 

 simjile. As in some other small sjiecies the glandular portion is a sim]ile canal 

 extending as far forward as the posterior end of the gonad whcic it bentls 

 abruptly and making its way posteriorly opens by an inconsjiicuous 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 californica, sp. nov. 



One specimen was collected in the neighboihood of San Diego, C'alifoi-nia, 

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

 l.() mm., the average thickness of the metathorax, and 2 mm. the average diame- 

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

 length of the vai'ious divisions of the body are shown (Plate 4, fig. (i). The color 



