No. 26.] ARTHROSTRACA OF CONNECTICUT. 239 



1905. Oniscus asellus, Paulmier, Bull. N. Y. State Mus., 

 No. 91, p. 180. 



Body oblong-ovate, about one and one^half times as long as 

 wide. Head twice as wide as long, with frontal margin slightly 

 convex, and pronounced antero-lateral lobes which are narrow 

 and elongated and rounded anteriorly. Eyes large, compound, 

 oval, situated at sides of head at base of antero-lateral lobes. 



First antennae very small and inconspicuous. Second pair 

 extending when retracted to posterior margin of third thoracic 

 segment, with first joint short; second and third subequal and 

 each twice as long as the preceding; fourth joint nearly twice as 

 long as third; and fifth joint one and a half times as long as 

 fourth; flagellum composed of three joints and shorter than last 

 peduncular joint. 



Thoracic segments of subequal length; first one with antero- 

 lateral angles produced to embrace head, extending nearly to the 

 extremity. of the antero-lateral angle of head. Coxal plates not 

 distinct but lateral margins of all the segments well expanded and 

 straight, producing an even contour. Legs moderately slender, 

 increasing in length posteriorly. 



Abdomen not abruptly contracted ; all the segments distinct, 

 the first two considerably shorter than the others and with their 

 lateral margins completely concealed by the last thoracic seg- 

 ment ; lateral margins of third, fourth, arid fifth segments ex- 

 panded, and produced and curved posteriorly to continue the 

 oval outline of the body, those of the fifth segment being produced 

 backwards strongly as far as the extremity of the last segment. 

 Terminal segment triangular with apex produced considerably 

 and pointed and convex above. Uropods rather produced, with 

 the inner ramus originating far in front of the outer; peduncle 

 extending beyond the middle of last abdominal segment; inner 

 ramus narrow, linear, reaching as far as apex of abdomen; 

 outer ramus narrow lanceolate, extending beyond the apex. 



Color, dorsal portion of body dark brown ; lateral margins of 

 body and longitudinal rows of spots on either side at union of 

 coxal plates and body segments, light yellow. 



Length i6 mm. 



Distribution ; Greenland ; Iceland ; Sweden ; Norway ; Den- 

 mark ; Great Britain ; France ; Spain ; Italy ; Azores ; also Woods 



