392 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



or quite concealed from above by the projecting angles of tlie segments, 

 and tlie " abdominal epimera" are mostly concealed beneath the pleon. 

 These organs are the much elongated inferior angles of the segments, 

 which in allied genera, as ^gathoa, are short and not produced. In a 

 lateral view they considerably resemble the posterior epimera, giving 

 the appearance of two additional pairs. The specimen first described is 

 smaller than others that have since been obtained. 



Nerocila munda Hargei'. 



Xerocila munda Harger, This Report, i)a.rt 1, p. 571 (277), 1374; Proc. U. S. Nat. 

 Mils., 1879, vol. ii, p. 161, 1379. 

 Verrill, Tins Report, part i, p. 4.59 (165), 1874. 



Plate X, Fig. 65. 



This si)ecies may be recognized among our Isopoda by the projecting 

 posterior epimera, and the two pairs of spiniform "abdominal epimera" 

 beneath the pleon. 



The body is oval, twice as long as broad, smooth, iiolished, and mod- 

 erately convex. The head is flattened, broader than long, narrowing 

 anteriorly, broadly rounded or subtruncate in front, three-lobed behind, 

 with the middle lobe largest. The eyes are black and consist of an 

 irregularlj" rounded patch of small indistinct ocelli, and are visible 

 both above and below. The ant ennui ce are about as long as the head, 

 and composed of eight segments, of which the first is short, the second 

 is the longest, and the remaining six decrease pretty regularly in size 

 to the last. The antennae are a little longer and more slender than the 

 antennultB and have the first segment short, the second subglobose, the 

 third, fourth, and fifth cylindrical, and a little larger than the segments 

 of the flagellum, which are about five in number. The mandibular palpi 

 are longer than any three segments of the antennae, and the first seg- 

 ment is large, the second elongate conical, the third shorter, cylindrical. 



The first thoracic segment is much longer than the succeeding ones 

 and adapted to the head in front. It is slightly produced at its lateral 

 angles behind, or rather appears so from the union of the epimera, which 

 really constitute the projecting angles to the segment. In the second, 

 third, and fourth segments the posterior angles are but little produced, 

 and are equaled or slightly surpassed by the epimera, but in the last three 

 segments the posterior angles are acutely produced much beyond the 

 epimera of the corresponding segments, the angle of the sixth segment 

 nearly attaining the end of the seventh epimeron. In a lateral view, 

 only the last two epimera are decidedly acute, while those of the second 

 and third segments are obtuse and rounded behind. Seen from below, 

 the posterior angles of the epimera are acute throughout. The first pair 

 of legs are slightly more robust than the second and third ; the last four 

 pairs are still more slender, the last pair longest, and the last two pairs 

 armed with a few short spinules. 



The pleon is shorter than the thorax and much narrower, though 



