A new Species of Nectonemertes. 347 



constant feature, in tlie type specimen having a globular form with 

 a diameter of nearly 0,5 mm in one specimen. 



Throughout the intestine and to a considerable extent in the 

 pylorus the epithelium is usually dislodged, owing possibly to the 

 rapid change of pressure on the journey upward or to violent 

 peristaltic movements. This latter process evidently ensued for 

 portions of the pyloric lining have been shifted into the adjoining 

 portions of the intestine, several fragments finding lodgment in the 

 outer blind ends of the coeca. In these latter locations throughout 

 the entire intestine it is possible to find portions of the intestinal 

 epithelium intact and in a fair state of preservation. The ordinary 

 type of cell is high and slender, with indistinct cell boundaries and 

 no trace of cilia but with cytoplasm filled with vacuoles and 

 numerous granules of various size and character. Among these is a 

 very much smaller number of club-shaped gland cells which carry 

 a globular mass of coarsely granular secretion. 



In this species three longitudinal vessels are present, a dorso- 

 median canal and two lateral channels, which unite in characteristic 

 hoplonemertean fashion in the extreme anterior and posterior ends 

 of the body. On each side of the proboscis sheath immediately 

 behind the dorsal commissure the median vessel, which has divided, 

 meets the lateral and the resulting vessels pass forward between 

 the two brain commissures and become continuous above the rhyncho- 

 coel at the extreme anterior end of the body. Posteriorly the median 

 and lateral vessels gradually approach each other and, after having 

 taken a position dorsal to the intestine in the tail region, unite 

 with each other a short distance in front of the rectum. In the 

 brain region the median vessel lies beneath the proboscis but soon 

 penetrates its walls and after having foi-med a ridge on the ventral 

 side of the rhynchocoel emerges in the region of the cirri. The 

 lateral vessels throughout most of the head and body closely follow 

 the lateral nerve cords and are accordingly ventral. Nowhere are 

 these larger vessels supplied with branches, nor are the relativly 

 small lacunae of the head and the central canal of the cirri connected 

 with them. 



Judged by the nuclei, the blood corpuscles are of two varities. 

 In both the amount of cytoplasm is small and in the more abundant 

 type the compact nucleus is approximately 0,0027 mm in diameter 

 while in the other it is upwards of twice as large and contains a 

 relativly small amount of chromatin. The walls of the blood vessels 



