CRUSTACEA.NS. 231 



the neck segment, very strongly defined from the cheeks and 

 the front margin (which latter is very prominent, and strongly 

 recurved and arched upward in the middle) by profound fur- 

 rows ; lateral lobes, particularly the two posterior pairs, dis- 

 tinctly defined by deep lateral furrows that curve a little back- 

 ward, the posterior pair being transversally or obliquely a 

 little oval and about three times as large as those of the next 

 pair, which are as much larger than the third pair, all being 

 nearly round; neck furrow well defined, neck segment about 

 of the same size as the first thoracic segment, often slightly 

 thickened at each end, arched a little forward, and nearly or 

 quite as high as the most prominent part of the glabella in 

 front. Eyes rather prominent, small, nearly surrounded, ex- 

 cepting on the inner side, by a shallow concavity, and situated 

 opposite the furrows between the anterior and middle lateral 

 lobes of the glabella ; visual surfaces very small, about twice 

 as long as high, a little arcuate and directed nearly laterally ; 

 palpebral lobes small, rather prominent, and capping as it were 

 the visual surfaces. Movable cheeks, with thick, rounded lat- 

 eral margins, defined by a distinct rounded marginal furrow, 

 continuous with that separating the anterior end of the gla- 

 bella from the prominent arched middle of the anterior margin. 

 Fixed cheeks provided with a very deep, broad furrow along 

 their posterior margins. Facial sutures directed forward ante- 

 riorly, so as to intersect the margins somewhat nearer together 

 than the breadth across between the eyes; posteriorly, some- 

 times slightly furrowed and directed at first a little obliquely 

 backward and outward from the eyes for less than half their 

 length, then curving somewhat abruptly, and extending more 

 obliquely backward nearly straight to, or very slightly in front 

 of the posterior angles of the cheeks ; rostral shield strongly 

 arched, about twice and a half as long, measuring directly 

 across from its lateral extremities, as the height from its upper 

 to the lower margin at the middle. Labrum or hypostome 

 longitudinally oblong with sinuous lateral margins ; anterior 

 end a little wider than any other part, with a convex outline, an- 

 terior margin prominent, rather deeply notched in the middle, 



