HAUSTORIIDAE OF NEW ENGLAND — BOUSFIELD 169 



Peraeopods 3 and 4, segment 2 with posteroproximal spinous process; only 

 one North Atlantic species known .... Priscillina armata (Boeck) 



4. Urosome segment 1 with mid-dorsal bifid prominence; anterolateral head 



lobe sharply acute; eyes large, reniform . Pontoporeia femorata Kr0yer 

 Urosome segment 1 dorsally smooth, finely pilose; anterior head lobe sub- 

 acute; eyes small, subovate Pontoporeia afBnis Lindstroni 



5. Gnathopod 2 weakly subchelate; maxilliped palp, segment 3 short, broad; 



uropod 3, inner ramus slender, longer than peduncle; telson incompletely 

 cleft Amphiporeia. 6 



Gnathopod 2 subfusiform, heavily setose; maxilliped palp, segment 3 

 slender, strongly arched; uropod 3, inner ramus lobate, shorter than 

 peduncle; telson typically cleft to base Bathyporeia 



Urosome segment 1 with dorsal and lateral spines. 



Bathyporeia quoddyensis Shoemaker (p. 171) 



6. Antenna 1 weakly geniculate; abdominal side plate 3 subquadrate, posterior 



margin gently convex; uropod 3 elongate, inner ramus and terminal seg- 

 ment of outer ramus subequal . . . Amphiporeia virginiana Shoemaker 

 Antenna 1 sharply geniculate; abdominal side plate 3 subacute, posterior 

 margin shallow-concave; uropod 3 medium-long, iimer ramus much longer 

 than terminal segment of outer ramus. 



Amphiporeia lawrenciana Shoemaker 



7. Peraeopod 2 distinctly smaller than and unlike peraeopod 1; coxal plates 



1 and 2 much smaller than 3 and 4; telson of two widely separated lobes. 



Eohaustorius (American Pacific) 



Peraeopods 1 and 2 subequal, similar; coxal plates 1 and 2 appreciably 



deep and broad; telson entire or variously cleft, lobes approximate . . .8 



8. Posterodorsal border of pleon segment 3 free or slightly decurved, not 



refiexed; urosome and uropod 1 strong, rami spinose; pleon side plate 3 



rounded 9 



Posterodorsal border of pleon segment 3 strongly reflexed forming a lobe 

 overhanging urosome; urosome short; uropod 1 slender, inner ramus with 

 spines and setae; pleon side plate 3 (except in Haustorius) with posterior 

 spinous process 15 



9. Body relatively slender, lateral lobes of peraeon weak; pleon gradually 



narrowing behind; head not broadened, rostrum weak; maxilliped palp 

 3rd segment not geniculate; maxilla 2, outer plate little larger than 



inner Protohaustorius, new genus. 10 



Body broadly arched, peraeon lobes pronounced; abdomen abruptly narrow- 

 ing beyond peraeon 7; head very broad, rostrum distinct; maxilliped palp 

 terminal segment geniculate; maxilla 2 with large, setose, outer plate . 11 



10. Coxal plate of peraeopod 2 much broader than deep, elongate behind; per- 



aeopod 5, posterior border of segment 4 narrower than anterior border, 

 with two spine groups; uropod 1, posterior margin of peduncle distally 

 spinose .... Protohaustorius deichmannae, new species (p. 173) 

 Coxal plate of peraeopod 2 little broader than deep; peraeopod 5, posterior 

 margin of segment 4 wider than anterior, with 3-4 spines; uropod 1, 

 posterior margin of peduncle spinose throughout. 



Protohaustorius wigleyi, new species (p. 175) 



11. Uropod 2 strong, biramous; telson broad, sharply or broadly cleft; antenna 2, 



peduncular segment 5 broad but not lobate behind; mandible with incisor. 



Parahaustorius, new genus. 12 



