102 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



HOPI.ONKMEUTEA. 



A. Proboscis sheath not more than three-fourths the length of body; 

 body long and slender . . . . . . . B. 



B. Proboscis sheath less than half the length of body; proboscis of 

 small size . . • ....... C. 



C. Accessory stylets present . . . . . . . D. 



D. Ocelli minute and usually numerous. EMPLECTONf:MA, p. 206. 



1. Stylets long and slender, curved; basis very long; color of 



body dark green or pale green above, whitish or very pale 

 greenish beneath . . . . E. gracile, p. 207. 



2. Stylets straight and short, with swollen heads ; basis of 



central stylet swollen and rounded posteriorly ; 11 Y'^'o- 

 boscidial nerves ; color of body dark brown above, often 

 with minute purple dots ; flesh-colored or yellowish white 

 beneath . . . . . . E. hiirgeri, p. 209. 



3. Stylets straight, without swollen heads, fluted longitudinally; 



basis of central stylet not swollen posteriorly ; 16 pro- 

 boscidial nerves ; color of body purplish or purplish brown 

 from closely placed mottlings on dorsal surface ; ventral 

 surface gray or yellowish . . E. purpurafum, p. 210. 



DD. Ocelli four in nimiber ; body filiform. Nemertopsis, p. 217. 

 1. Length often 15 cm. or more; very pale brown or whitish, 

 with 2 longitudinal dorsal stripes of deep brown ; 8 pro- 

 boscidial nerves . . . . N. gracilis, p. 217. 



CC. Accessory stylets absent ; ocelli large, two in number ; pro- 

 boscis and sheath very rudimentary, with central stylet only ; 

 parasitic .... Carcinonemertes, p. 230. 

 1. Length when sexually mature but 4 to 6 mm. ; color orange or 

 reddish ; parasitic on egg masses of Epialtus and j)erhaps 

 other crabs ..... C.epialti, \\. '2'-^\. 



BB. Prol)Oscis sheath one-half to three-fourths the length of body; 

 proboscis well developed . . Paranemertes, p. 219. 



1. Two or four pouches of accessory stylets ; 14 proboscidial nerves ; 



stylets slender, spirally grooved ; color purplish brown, dark 

 brown, or orange-brown above, on sides, and on lateral margins 

 of ventral surface ; with a whitish angular spot on each side of 

 head ; ventral surface (often only the median thijxl) white or 

 yellowish white ..... P. pe7-egrinn, -p. 220. 



2 . Four poixches of accessory stylets ; 9 or 1 proboscidial nerves ; 



color opaque white ..... P. pallida, p. 224. 



3. Four or six jiouches of accessory stylets ; 10 large proboscidial 



nerves ; translucent, pale orange anteriorly, flesh color, grayish 



