338 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



epimera are separated by sutures, except in the first segment, and have 

 their posterior angles acute. The first three pairs of legs have the dac- 

 tylus capable of complete flexion upon the propodus, which is more or 

 less swollen and supported by the short triangular carpus. In the last 

 four pairs of legs the three corresponding segments are nearly cylindri- 

 cal and the dactylus is incapable of complete flexion on the propodus. 



The pleon, or abdomen, is convex throughout and pointed at the tip, 

 and is composed, apparently, of five segments, of which the first three 

 are separated by complete sutures, but the last two are united in the 

 dorsal region, the sutures separating them being visible only at the 

 sides. The opercular plates consist, on each side, of an elongated, 

 vaulted, and attenuated plate, regularly rounded at the anterior end, 

 truncate at the apex, and bearing just within the apex, on the inner side 

 of the organ when closed, two ciliated, ovate or triangular plates. Of 

 these the internal plate, or the one next the median line is much smaller 

 than the outer; the outer also overlaps the inner, a disposition similar to 

 that which prevails in the branchial plates or pleopods. The basal plate 

 of the operculum is ciliated along its anterior and inner margin with 

 bristles, which are plumose except in the region nearly opposite the 

 articulation of the plate, where they become stouter and spine-like. The 

 stylet on the second pair of pleopods in the males is long and slender, 

 more than twice the length of the lamella to which it is attached. 



Chiridotea cceca Harger (Say). 



Idotea caeca Say, Jour. Acad. Nat. Sci. Phil., vol. i, p. 424, 1818. 



Hitchcock, Rep. Geol. Mass. , p. 564, 1833. (/. caeca ? ) 



Gould, Rep. Geol. Mass., 2ded., p. 549, 1835; Invert. Mass., p. 337, 1841. 



Edwards, Hist. nat. des Crust., torn, iii, p. 131, 1840. 



Gu6rin, Iconog. , Crust. , p. 35, 1843. 



Dekay, Zool. New York, Crust., p. 42, 1844. 



White, List Crust. Brit. Mus., p. 94, 1847. 



Verrill, This Report, part i, p. 340 (46), 1874. 



Harger, This Report, part i, p. 569 (275) ; pi. v, fig. 22, 1874. 

 Chiridotea caeca Harger, Am. Jour. Sci., Ill, vol. xv, p. 374, 1878; Proc. U.S. 

 Nat. Mus., 1879 3 vol. ii, p. 159, 1879. 



PLATE IV, FIGS. 16-19. 



This species is at once distinguished from the following by its larger 

 size and short antennae, which surpass the antennulae but little, if at all. 

 Among the other known Isopoda of the New England coast, it may be 

 recognized by the broad, subcircular thorax, joined with an articulated 

 flagellum of the antennae and a two-valved abdominal operculum. The 

 eyes are, moreover, light-colored and inconspicuous, whence the name. 



The head is but slightly excavated in front for the bases of the an- 

 tennae, and there is a more or less open notch at the sides extending 

 nearly to the eyes. The antennulae (pi. IV, fig. 17 a) Jire longer than 

 the peduncle of the antennae and have the second segment strongly 

 clavate; the third cylindrical; the last with about a dozen tufts of short 



