230 bulletin: museum of comparative zoology. 



large nephridial canals found near the blood vessels as in related 

 species. Very fine canals, however, which very likely belong to the 

 nephridial system, are scattered loosely in the parenchyma. It 

 seems probable, therefore, that the nephridia are diffused, as in 

 Stichostemma. 



Habitat. — Individuals of this species are rather common in sand 

 at low water at San Diego and San Pedro, California. Occasionally 

 found on piles of wharves. The worms exude an abundance of a 

 milky mucus when handled, and are very peculiar because of their 

 translucency and the deep green pigment of their intestinal canals. 



Carcinonemertes Coe. 

 Amer. Nat., 36, p. 440, 1902. 



Parasitic nemerteans living on various species of crabs and some- 

 times other Crustacea. Body small, slender, filiform, rounded, and 

 of al)Out the same diameter throughout ; head without distinct lat- 

 eral grooves. Body not coiled or twisted, but often folded sharply 

 so that anterior portion of body lies parallel and in contact with 

 posterior portion. Mouth and ])roboscis open together ; esophagus 

 extremely short, opening broadly into intestine through a large mus- 

 cular chamber (stomach) situated immediately behind l)rain ; intes- 

 tine broad, with short lateral })ouches which are but little develo]»ed 

 in posterior portion of body ; pylorus and intestinal caecum practi- 

 cally wanting. 



Proboscis sheath without muscular walls, consisting merely of a 

 thin membrane closely a})plied to the small proboscis. Proboscis 

 but little developed, very small in size, and extremely short, without 

 lateral pouches of reserve stylets, but armed with minute central 

 stylet and l>asis only. Stylet region of ])roboscis can be withdrawn 

 but little behind brain ; consequently anterior chamber is very short, 

 without distinct miiscular layers, without distinct nerves, and with- 

 out a thickened glandular epithelium such as occurs in almost all 

 other nemerteans. Chamber immediately behind stylet small but 

 muscular, and with a lining of flattened ei)ithelium, while posterior 

 proboscidial cavity is very short, often almost si)herical, highly 

 glandular, connected closely with the rudiments of the proboscis 

 sheath and iml)edded in the connective tissue which lies internal to 

 the body musculature. 



