278 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



3. Proboscis sheath nearly as long as body ; proboscis long and slen- 

 der ; usually 2 pairs of large ocelli Prosorhochmidae 



4. Intestinal diverticula branched ; intestinal caecum usually with 

 long anterior branches ; gonads irregularly grouped ; ocelli usu- 

 ally numerous Amphiporidae 



4. Intestinal diverticula unbranched ; intestinal caecum v^^ith short 

 anterior branches or none; gonads alternate regularly with 

 intestinal diverticula; ocelli usually 4 . . . Tetrastemmatidae 



Family Emplectonematidae 



Five genera found on the Pacific coast are included in this family. 



Key to Genera 



1. Parasitic on crabs; cerebral sense organs absent; proboscis rudi- 

 mentary and accessory stylet pouches absent . . Carcinonemertes 



1. Free living; cerebral sense organs present; proboscis with 2 or 

 more pouches of accessory stylets 2 



2. Head with numerous small ocelli or with a small cluster on each 

 side of proboscis opening 3 



2. Head with 4 ocelli 4 



3. Body very slender; proboscis sheath less than half as long as 

 body; proboscis with only 2 or occasionally 3 pouches of acces- 

 sory stylets Emplectonema 



3. Body only moderately slender; proboscis sheath 3^ to ^ as 

 long as body; proboscis with 2, 4, or 6 pouches of accessoiy 

 stylets Paranemertes 



4. Body filiform; ocelli large Nemertopsis 



4. Body firm and only moderately slender; ocelli very small . . 



, Dichonemertes 



Genus EMPLECTONEMA Stimpson 

 Key to Species 



1. Dorsal surface green; central and accessory stylets curved; 

 stylets long and slender; basis very long; body dark or pale 

 green dorsally; whitish, yellowish, or very pale green ventrally 

 gracile 



1. Dorsal surface brown or purplish; central and accessory stylets 



straight 2 



