No. 26.] ARTHROSTRACA OF CONNECTICUT. II7 



twelve to sixteen segments. Second antennae much shorter than 

 first; last two joints of peduncle subequal in length; flagellum 

 not exceeding the peduncle in length, composed of five to nine 

 segments. 



First four coxal plates well developed and much deeper than 

 their segments with lower margins setose. 



First gnathopods stouter but shorter than second ; carpus 

 short, subtriangular ; propodus broader than carpus, with oblique, 

 finely pectinated palm which is as long as hind margin 

 and separated from it by two large spines. Second gnathopods 

 with carpus narrowly triangular, with a fascicle of setae at lower 

 posterior angle ; propodus widening regularly toward distal end, 

 palm oblique, finely pectinated, rounded posterior angle armed 

 with two stout spines ; propodus and carpus taken together form- 

 ing an elongated triangle. Pereiopods very spiny ; dactyl narrow 

 over half as long as propodus; basal joint of third pair of pereio- 

 pods expanded and prolonged slightly distally behind ; basal 

 joint of last pair not expanded. 



First four abdominal segments armed dorsally with a strong 

 posterior spine. Postero-lateral angle of third segment produced 

 and acute. 



Second pair of uropods much shorter than first or third ; rami 

 provided with a long terminal spine and several shorter lateral 

 ones; terminal uropods extending a little beyond first pair; rami 

 subequal, flattened, much longer than peduncle. 



Telson much elongated, extending nearly to tip of posterior 

 uropods, cleft nearly to base ; lobes denticulated at apex and 

 furnished with several tufts of spines near lateral margins and one 

 or more at distal end. 



Length 3 mm. 



Distribution : Norway ; British Isles ; France ; Woods Hole, 

 Massachusetts ; Noank Harbor (taken at the surface in the 

 evening, July 13, 1874), ofif Stonington, Connecticut; Long Island 

 Sound. 



ORCHESTIID^. 



Mouth parts strorigly projecting downwards. 



First antennie usually much shorter than second pair ; without 

 accessory flagellum. Second antennae with first joint of peduncle 

 coalesced with the head. 



