no. 1654. AMPHIPODA FROM WEST NORTH AMERICA— HOLMES. 5H 

 AMPELISCA PACIFICA, new species. 



First antennae very slender, scarcely one-fourth the length of the 

 body, the tumid first joint about a third the length of the .second and 

 about equal to the third; flagellum longer than peduncle and com- 

 posed of about ten or twelve narrow joints. Peduncle of second anten- 

 nae about as long as first pair, the last joint of the peduncle four-fifths 

 the length of the preceding one. First gnathopods with hand shorter 

 than carpus; hand of second gnathopods about half the length of car- 

 pus. Dactyl of first and second perseopods longer than the two pre- 

 ceding joints combined; merus of first peraeopods produced in front 



Fig. 20. — Ampelisca pacifica, female, a\, first antenna; a&i, fourth abdominal 

 segment ; gn, gnathopod ; p t , fourth per.bopod. 



nearly to distal end of carpus ; much less strongly produced in second 

 pair. Fourth pera?opods with spines on anterior margin of carpus 

 and propodus. Tail of basal joint of last peraeopods produced to 

 middle of merus ; ischium broader than long ; merus produced down- 

 ward posteriorly to beyond middle of carpus and bearing about six 

 long plumose setae on outer side of expansion, and a spine at the tip; 

 carpus as long as merus on posterior side, armed with several spines 

 at lower extremity, both in front of and behind propodus, and a 

 single spine on anterior margin ; dactyl attenuate at tip, shorter than 

 propodus. Infero-posterior angle of third abdominal segment pro- 





