COE: NEMEKTEANS OF WEST AND NORTHWEST COASTS. 143 



Habitat. — Common in rather sandy locations on the flats in San 

 Pedro Harbor, California, from half-tide to low water. Also under 

 stones at Dead Man's Island, San Pedro. The species is often asso- 

 ciated with a small white species of Cakinoma (C mutabilis), 

 which it so closely resembles in size and color in life as to be easily 

 mistaken by a merely superficial examination. The presence of dis- 

 tinct intestinal diverticula and the broad and flattened posterior 

 extremity of the latter genus, however, will serve to distinguish it. 

 After preservation the reddish brown band which appears in Cari- 

 NOMELLA renders the identification very easy. A white Carinella 

 {C pellucida) has been collected in the same locality, but this is 

 always minute in size and very slender. A whitish Zygeupolia 

 (Z. littoralis) is also found at San Pedro, but this may easily be 

 recognized by its narrow, pointed head. And, finally, pale, imma- 

 ture individuals of Micrura griffini occur in the same locality, but 

 the presence of lateral cephalic furrows will distinguish this species 

 from the above mentioned. 



Carinoma Oudemans. 

 Quart. Journ. Micr. Sci., 25, SuppL, pp. 1-80, 1885. 



Body usually slendei-, often thickened and rounded anteriorly, 

 flattened in intestinal region ; head usually wider than parts imme- 

 diately following ; mouth situated immediately behind the brain ; 

 proboscis pore subterminal. Lateral slits, cephalic grooves, ocelli, 

 and cerebral sense organs wanting, although a row of sensory pits 

 occurs in the median line on the dorsal side of the head in at 

 least three of the four known species. Intestine with paired, lateral 

 diverticula. 



Body musculature composed of two muscular layers throughout 

 length of body, and of localized supplementary layers. These con- 

 sist of a thick internal longitudinal layer and a thin external circu- 

 lar layer, but in the esophageal region a second circular layer lies 

 internal to the longitudinal muscles, and just in front of the 

 nephridial region becomes enormously thickened. In the anterior 

 portions of the esophageal region a double set of distinct diagonal 

 muscles lies just internal to the outer circular muscular layer. 



The lateral nerves are situated within the longitudinal muscu- 

 lar layer. 



