ALASKA NEMERTEANS 37 



numbers to the commencement of the intestinal region. In front of 

 the brain is a large and irregular cluster of glands, which open ante- 

 riorly on the tip of the snout. 



Cerebral sense organs. — Situated in front of brain, and near latero- 

 ventral margins of head. The ducts which place them in communi- 

 cation with the exterior run obliquely forward and downward, and 

 open immediately on the surface, 



Nephridia. — The nephridial canals extend from near the brain 

 throughout almost the entire esophagal region. The main trunks lie 

 above the lateral nerve cords, and send off numerous branches both 

 ventral and dorsal to the nerves. There is a single pair of remarkably 

 large efferent ducts opening just below the lateral margins of the 

 body, and slightly anterior to the middle of the esophagal region. In 

 one series of sections these ducts are so precisely paired that both ap- 

 pear in a single section (pi. xii, fig. i). The efferent ducts pass 

 from above obliquely downwards and external to the nerve cords. 



The blood-vascular system consists of cephalic lacunag, and anasto- 

 mosing longitudinal vessels, as in related genera. 



The intestinal cascum does not reach forward nearly to the brain. 

 There are comparatively few lateral diverticula (p1. xii, fig. i). 



The lateral nerve cords unite above the posterior end of the intestine. 



Parane7nertes pallida was found only at Yakutat and at Sand Point 

 on Popof Island, and few specimens were obtained. These were 

 about 150 mm. to 250 mm. in length, and perhaps 5 mm. in width. 

 They were found between tides under stones covered with algse. 



12. PARANEMERTES CARNEA sp. no v. 



pi. Ill, figs. 3, 4; p1. VII, fig. 4 ; p1. VIII, fig. 7. 



This species was found to be extremely variable in size, shape of 

 body, and head, and especially in the armature of the proboscis. As 

 shown in pi. iii, figs. 3 and 4, the body is rather stout, rounded in 

 the esophagal region, flattened both above and below posteriorly, and 

 ending rather abruptly behind. The head is very variable in shape, 

 being pointed, rounded, broadened, or emarginate in front, according 

 to its state of contraction. It is most commonly a little broader than 

 the parts immediately following, and is not distinctly marked off, 

 although a slight oblique furrow on each side is sometimes seen behind 

 the brain. From the dorsal surface the furrows of the two sides give 

 the appearance of a very faint V-shaped marking with the angle pro- 

 jecting backward in the median line. A little farther forward, as 

 seen in p1. viii, fig. 7, a pair of shallow furrows occupies the sides of 



