NO. 13 COE : REVISION OF THE NEMERTEAN FAUNA 303 



81. Amphiporus rubellus Coe, 1905 



A. rubellus Coe, 1905a. 



Habitat. Among mussels and other growths on spiles of wharf and 

 on rocks at low-water mark ; more common at depths of 35-200 m off the 

 coast. 



Distribution. At present known only from southern California. 



82. Amphiporus tigrinus Coe, 1901 



A. tigrinus Coe, 1904, 1905, 1905a. 



Habitat. Under stones between tidemarks. 



Distribution. At present known only from British Columbia and Pa- 

 get Sound. 



Family Tetrastemmatidae 



This family is represented on the Pacific coast by 3 genera, of which 

 one is found only in fresh-water lakes and pools. 



Key to Genera 



1. With 4 or 6 ocelli ; lives only in fresh- water lakes and pools . . 



Prostoma 



1. With 4 ocelli or none; marine 2 



2. Ocelli absent; hermaphroditic Amphinemertes 



2. Ocelli 4, occasionally fragmented ; sexes separate in most species 



Tetrastemma 



Genus AMPHINEMERTES, new genus 



Body slender and almost cylindrical; minute; proboscis sheath extends 

 entire length of body; proboscis very large, equal to diameter of body 

 when everted; armature typical for family; intestinal caecum extends 

 forward almost to brain; cerebral sense organs large, situated against 

 anterior and ventral surfaces of brain; ocelli absent; hermaphroditic. 



A single species belonging to this genus has been reported from the 

 coast of Alaska. 



