NO. 1 BARNARD: AMPHIPODA OF THE FAMILY AMPELISCIDAE 7 



15. Lower front edge of head subparallel to upper margin . 16 

 15. Lower front edge of head oblique . . . panamensis 



16. Post edge pleon 3 Insinuate brevisimulata 



16. Post edge pleon 3 not bisinuate 17 



17. Posterior edge of pleon segment 3 nearly straight . .18 



17. Posterior edge of pleon segment 3 strongly convex . .19 



18. Pleon segment 3 with a strong tooth .... hancocki 



18. Pleon segment 3 with a weak tooth .... shoemakeri 



19. Article 4 of peraeopod 5 strongly produced . . .21 



19. Article 4 of peraeopod 5 not strongly produced . . 20 



20. Anterior edge of article 5 of peraeopod 5 notched, apex of outer 



ramus of uropod 2 without long spine .... eschrichtii 

 20. Anterior edge of article 5 of peraeopod 5 smooth, apex of outer 



ramus of uropod 2 with long spine .... macrocephala 



21. Pleon segment 3 with a strong tooth 22 



21. Pleon segment 3 weakly produced .... indentata 

 22. Uropod 1 reaching to end of uropod 2 mexicana 



22. Uropod 1 reaching only slightly beyond end of peduncle of 



uropod 2 23 



23. Gnathopod 1 strongly subchelate gnathia 



23. Gnathopod 1 weakly subchelate pugetica 



Ampelisca catalinensis, new species 

 Plates 1 and 2 



Description of female: Head longer than first 2 body segments, an- 

 terior edge of head incised, lower front margin oblique, concave. Corneal 

 lenses absent. 



Antenna 1 reaching well beyond end of peduncle of antenna 2; 

 article 2 of peduncle more than twice as long as 1, article 3 shorter 

 than 1. 



Antenna 2 about as long as body; article 5 of peduncle four fifths 

 as long as 4. 



Mandible: spine row with 10 spines; article 3 of palp about two 

 thirds as long as 2. 



Maxilla 1 : outer plate armed with 1 1 spines ; article 2 of palp 

 wider than outer plate, armed with 5 spines, 4 cusp teeth, and 8 setae. 



Maxilliped: inner plate reaching to end of palp article 1, armed 

 with 3 chisel teeth ; outer plate reaching almost to end of palp article 2, 

 inner edge with 10 chisel teeth, rounded apex with 9 spines and setae, 

 the outermost 5 plumose. 



