186 BULLETIN: MUSEUM OF COMPAEATIVE ZOOLOGY. 



animal was well extended. The histological peculiarities of the 

 various portions of the alimentary canal are perfectly similar to 

 those described for Linens rubescens (p. 165). 



At the posterior end of stomach region and anterior to the first 

 pair of intestinal lobes is a highly developed inner circular muscle 

 similar to that described for Zygeupolia. It terminates abruptly 

 after having attained its maximum development and extends anteri- 

 orly but a short distance. 



In the same region occurs a corresponding thickening of the cir- 

 cular muscles both of the proboscis sheath and of the body walls. 



JSlood system. — The large, median cephalic lacuna divides into 

 lateral lacunae, and these into a system of esophageal lacunae, as in 

 related species. Behind the nephridial region the esophageal lacunae 

 are again united into the lateral vessels. 



Nephridla. — The ne])hridial canals extend from near the mouth 

 nearly to anterior end of the stomach region. Anteiiorly a number 

 of slender branches ramif}^ among the esophageal lacunae, but are 

 soon gathered into a single longitudinal canal on each side. This 

 canal has a few large branches and opens at its posterior extremity 

 to the dorso-lateral surface of the body by an unusually large efferent 

 duct. The pair of nephridiopores is thus situated a few sections in 

 front of the anterior end of the stomach. 



NervoHS system Siwd cephalic sense orsfans ai'e as in related species 

 in most particulars. The esophageal nerves, however, aie peculiar 

 in that the}^ each branch soon after their origin from the ventral 

 ganglia into two nerves of about equal size. One of these passes 

 through the circular muscles of the body walls at the anterior bor- 

 der of the mouth region and takes up the usual position beneath the 

 anterior portion of the esophagus. The other continues backward 

 through the greater portion of the esophageal region ]n'0])er directly 

 beneath the lateral nerve, and therefore outside the circular muscles. 

 In the stomach region the nerve is gradually fused in the general 

 nerve plexus on the outer border of the circular muscles. 



Reproductive 07'gans. — Sexual products are mature in September. 

 They develop in large pouches which largely obliterate the intestinal 

 canal when fully mature. 



Habitat. — Pacific Grove, California ; among crevices of rocks at 

 low water. Not common. 



A single specimen indistinguishable from the above after preser- 



