228 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



of the second antenna. Second antennas more than half as long 

 as body with the peduncular joints increasing in length to the 

 fourth; fifth joint a little shorter than fourth; flagellum made up 

 of a single joint a little longer than fourth joint. 



First segment of thorax slightly shorter than any of the others 

 except the seventh; second to fifth segments subequal in length; 

 sixth joint, a little shorter than the preceding ones ; third segment 

 broadest. Coxal plates distinctly separated on all the segments 

 including the first, placed in the first three segments on the 

 lateral margin anterior to the middle, in the fourth segment at 

 the middle, and in succeeding segments behind the middle; pro- 

 ducing a somewhat angular appearance to the otherwise very 

 even outline of the body. Legs ambulatory and furnished with 

 bi-unguiculate dactyls. 



Abdomen composed of only a single segment ; with a small 

 lateral process on either side about one-third the distance from 

 the base to posterior end ; posterior to the lateral processes the 

 sides are parallel for about one-half the distance and then con- 

 verge to a rounded apex. Operculum with basal plate more than 

 three times as long as broad, and terminal plate elongated and 

 obtusely triangular. 



The color in life is usually uniform dark green, sometimes 

 with an obscure dorsal stripe of a lighter color. 



Length 15 mm. 



This species has been collected at Great Egg Harbor, New 

 Jersey ; and Noank, Connecticut. It is not a common species 

 although it was abundant on eel-grass at the first mentioned 

 locality in April, 1871. 



It may be distinguished from the other genera of isopoda of 

 Connecticut by the flagellum of the second antennae which is 

 clavate and from the following species by its slender form and 

 regular outline. 



Erichsonella filiformis (Say). 



1818. Stenosoma filiformis, Say, Jour. Acad. Nat. Sci. Phila., 

 vol. I, p. 424. 



1874. Erichsonia filiformis, Harger, Rept. U. S. Com. Fish, 

 for 1871-2, p. 570. 



