No. 26.] ARTHROSTRACA OF CONNECTICUT.' 55 



First antennae as long as head and first two thoracic segments 

 together, with thick peduncle, the first joint of which is more than 

 twice as long as the other two combined ; fiagellum not quite twice 

 as long as peduncle; accessory fiagellum not quite half as long a? 

 fiagellum, made up of seven joints. Second antennae half again 

 as long as first pair; fiagellum made. up of about 28 segments. 



First gnathopods with propodus as long as carpus with palm 

 somewhat arcuate and finely serrated but not defined below by 

 prehensile angle. Second gnathopods with propodus half as long 

 as carpus. Two posterior pairs of pereiopods rather elongated, 

 with basal joint of moderate size. 



Anterior coxal plates more than twice as deep as respective 

 segments and increasing in height posteriorly ; fourth pair pro- 

 duced below the posterior emargination to a narrow lobe, obtuse 

 at the tip; fifth pair nearly as deep as broad. 



Third abdominal segment with postero-lateral angles drawn 

 out to very short point. 



Last pair of uropods with inner ramus scarcely longer than 

 basal joint of outer. Telson nearly twice as long as broad, slightly 

 tapering distally and with two pairs of dorsal denticles, and 

 very narrow cleft extending almost to the base. 



Length 15 mm. 



Distribution; Arctic regions; Norway; British Isles; Iceland; 

 Greenland; Labrador; Woods Hole, Martha's Vineyard, Massa- 

 chusetts. 



The species ranges in depth to over 600 fathoms. 



Tmetonyx quadratus sp. no v. 



Head produced to a small rostrum ; interantennal lobes 

 rounded. Body stout. 



Eyes oval ; deeply pigmented in alcoholic specimens. 



First antennae scarcely as long as head and first two thoracic 

 segments together, with short peduncle about two-thirds as long 

 as fiagellum; first joint of peduncle large, more than half as 

 broad as long; second and third joints short; accessory fiagellum 

 half as long as principal one and made up of six joints. Second 

 antennae over a third as long as body; last two joints of peduncle 

 subequal in length ; fiagellum with calceoli and made up of about 

 twenty segments. 



