310 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The first thoracic segment is excavated in front for the head, admitting 

 it about to the eyes. The next five segments are each a little longer 

 than the first, but the last thoracic segment is the shortest. The first 

 segment is dilated at the sides to about twice its length on the median 

 line. The second, and in an increasing degree the succeeding segments 

 are produced backward at the sides. The legs are rather small and 

 weak and of nearly equal size throughout. 



The first two segments of the pleon have their lateral processes, or 

 coxse, obsolete as usual in the family, but the third, fourth, and fifth 

 segments are produced laterally into broad plates, which are . close to- 

 gether, and, at their extremities, continue the regular oval outline of 

 the body with scarcely a perceptible break between the thorax and the 

 pleon. This outline is further continued by the expanded basal seg- 

 ments of the uropods, which are even larger than the adjacent coxse 

 of the fifth segment. At the extremity of the pleon both pairs of rami 

 are visible, the inner springing from near the base of the basal segments 

 below, the outer from a notch near the middle of the inner margin of 

 the basal segment. The rami are tipped with sette, and the inner just 

 surpass the outer, which, in turn, surpass the produced portion of the 

 basal segments. 



Length 4""», breadth 2"»™. Color in life slaty gray. 



This species was collected by Professor Yerrill, at Savin Eock, near 

 New Haven!, and also at Stony Creek!, Long Island Sound, in company 

 with Philoscia vittata Say. 



Specimens examined. 



The genus Ligia Fabricius* is recorded by Gould t from the timbers of 

 a wharf, probably in Boston, and by Dr. Leidy, | with some doubt, from 

 Point Judith, E. I., and the characteristics of the genus are therefore 

 here briefly inserted, as follows : 



Antennae with a multiarticulate flagellum ; basal segment of uropods 

 exserted bearing two elongated cylindrical rami. 



They are found usually in rocky places and under stones just above 

 high- water mark. They are common on our southern coast, and are 

 probably, at least occasionally, transported by accident within our lim- 

 its. I have seen no specimens from nearer than Fort Macon, N. 0. 



"~~ »Suppl. Eut. Sy8t-.,p. 296, 1798. 



t Invert. Mass., p. 337, 1841. 

 t Jour. Acad. Nat. Sci., II, vol. iii, p. 150, 1855. 



