NEMERTEANS 



I 49 



except that the cells in the lateral diverticula are provided with a 

 peculiar granular pigment which gives them a deep green color. 

 The same pigment occurs in the intestine proper, and is conspicuous 

 in life, giving the body a large portion of its characteristic coloring. 

 It is insoluble in alcohol, cedar oil, or the mounting media, and is far 

 more conspicuous in preserved specimens after they have been placed 

 in clearing oil. In the ca3cum the pigment is limited to the lateral 

 diverticula, and is not found in the central canal. 



Toward the posterior end of the caecum the diverticula become 

 longer and the canal gradually takes on the character of the intestine 

 proper near the most anterior sexual glands. The intestinal diver- 

 ticula are very closely placed, and for the most part fork once or twice 

 into two or four similar branches. These are very conspicuous in 

 life or after clearing in oil, because of their deep green pigment, as 

 stated above. Other than in the presence of this peculiar pigment the 

 histological structure of intestine is as in related forms. 



Blood and Nephridial Systems. In the head, as well as posterior 

 to the brain, the blood vessels branch out into very numerous branches, 

 which ramify through the parenchyma, including both that which lies 

 internal to the inner longitudinal muscles and that between the two longi- 

 tudinal muscular layers which are described above. The vessels are all 

 of small size, and extend on all sides above proboscis sheath and beneath 

 esophagus, as well as laterally. Back toward the intestinal region 

 they form the usual pair of lateral vessels. The proboscis sheath ves- 

 sel is as in related species. 



In regard to the nephridia, it is necessary to state that no well- 

 developed nephridial tubules were found, although several series of 

 sections were examined carefully back as far as the anterior sexual 

 glands. A number of very fine tubules in the esophageal region may 

 possibly represent the nephridial system, although they were scarcely 

 to be distinguished from blood vessels. There were some indications 

 that these tubules were connected with several very minute efferent 

 ducts opening to the surface laterally, but this could not be demon- 

 strated with certainty in any case. 



Reproductive Organs. Sexual products had evidently been re- 

 cently discharged from individuals collected near the end of July. 

 The ducts, which still remained open, connected with the dorso-lateral 

 surfaces of the body. 



Habitat. Individuals of this species are rather common in sand 

 at low water in San Diego Harbor. They were also obtained from 

 sandy locations on Dead Mans Island, San Pedro. A single specimen 



