MARINE ISOPODA OF NEW ENGLAND, ETC. 339 



setae ; the peduncular segments are bristly, as are also those of the an- 

 tennae. The first segment of the antennae (pi. IV, fig. 17 6) is very short, 

 the second about three times as long, longer than any of the following 

 segments; the third is longer and more slender than the fourth, which 

 is nearly as broad as long; the fifth, or last peduncular, segment is more 

 slender than any of the preceding, slightly clavate, about twice as long 

 as broad, and longer than any except the second. The flagellum slightly 

 exceeds the last two peduncular segments in length and consists usually 

 of about seven segments, each bearing a tuft of short hairs near its 

 extremity, except the first, which is much the longest, bears two such 

 tufts, and is, apparently, composed of two segments united. 



The breadth of the thorax is greater than its length along the median 

 line. The first pair of legs (pi. IV, fig. 18 I) are a little shorter than the 

 next two pairs, and the propodus or penultimate segment is a little more 

 swollen. The carpus becomes slightly more elongated in the next two 

 pairs. The last four pairs of legs are alike in form and increase in size 

 to the sixth pair, which is the largest. The legs are bristly hairy, 

 especially on the ischial, meral, and carpal segments, where they are 

 provided with stout setae curved at the tip. The basal segments bear 

 longer and more slender plumose hairs. The epimera are ciliated on 

 their external margins as are the lateral borders of the head and first 

 thoracic segment and the tip of the pleon. 



The operculum (pi. IV, fig. 18 c) is also ciliated with very fine hairs 

 along its postero-exteraal margin; the larger of the apical plates is 

 broader than in the following species, the width being to the length as 

 6 to 10. The stylet on the second pair of pleopods in the male (pi. IV, 

 fig. 19 &) considerably surpasses the cilia and is curved and acute at 

 the tip. Adult males and females seem to be comparatively rare, and 

 a common form of the secand pair of pleopods (pi. IV, fig. 19 a) presents 

 an acute stylet, imperfectly separated from the lamella and but slightly 

 surpassing it in length, strongly ciliated like the lamella on its margin. 



Length 12-15 mm ; breadth 6-8 mm . The color in life is variable but usually 

 dark grayish, much like the wet sand in or on which it is commonly found. 

 It may be more particularly described as usually of a dark leaden gray 

 on the top of the thorax, sometimes with a central spot, which may be 

 bright pea-green, probably from the contents of the digestive cavity 

 showing through. This dark color is continued in an arrow-shaped, or 

 halberd-shaped, spot occupying most of the upper surface of the head. 

 At the sides of the head and body is a mottling of light yellowish gray, 

 darker again on the edge. The under surface of the body and the legs 

 are pale and generally uniform in color. In alcohol the colors usually 

 fade to a uniform straw color, with fine blackish dots, which are less con- 

 spicuous in life. 



According to Say this species extends as far south as Florida. It is 

 common on sandy beaches at many localities on the coast of New Eng- 

 land, as at New Haven! and other localities on Long Island Sound!, 



