No. 26.] ARTHROSTRACA OF CONNECTICUT. 95 



First antennae slightly more than half as long as the body; 

 accessory flagellum composed of two joints. Second antennae 

 half as long as first pair. 



First gnathopods in male with propodus having palm slightly 

 oblique; second gnathopods with propodus increasing in width 

 distally and more elongate than in first pair, palm oblique, some- 

 what arcuate. Third, fourth, and fifth pereiopods with basal 

 joints serrate and with small spines on both margins. 



Postero-lateral angles of the first three abdominal segments 

 produced and terminating in a small tooth. 



Third uropods reaching apex of second pair ; outer ramus 

 nearly twice as long as peduncle, inner ramus minute, unarmed. 

 Telson slightly shorter than peduncle of last uropods, about as 

 broad as long, cleft about one-third the distance to the base and 

 with two or three spines on the truncate extremities of the lobes. 



Length 7-18 mm. 



Distribution : Lakes Superior and Huron ; Irvington, Indiana ; 

 Dalaware, Ohio ; Nashville, Tennessee ; Providence, Rhode 

 Island ; New Haven, Connecticut. 



Crangonyx Bate. 

 Similar to Eiicrangonyx, except that terminal uropods have 

 a single uniarticulate ramus and the telson may be entire or partly 

 cleft. 



Crangonyx tenuis Smith. 



1874. Crangonyx tenuis, Smith, Rept U. S. Fish. Com., 

 1872-3, p. 656. 



Body elongated and slender; coxal plates lower than their 

 respective segments ; last two abdominal segments fused. First 

 three abdominal segments longer than last three of thorax ; but 

 fourth, fifth, and sixth together scarcely longer than third. 



Eyes invisible in alcoholic specimens; interantennal lobes 

 small, rounded, projecting. 



First antennae less than half as long as body in the male, 

 with flagellum composed of about twenty-two segments and 

 twice as long as the peduncle, the first joint of which is slightly 

 longer than the second and the last joint about one-third as long 

 as the first; accessory flagellum very small, composed of two 

 joints, the terminal one of which is very short. Second antennae 



