86 CRUSTACEA. 



SUBFAMILY PISINJE. 

 HTAS LYRATUS. 



Carojxix* lyratus, parce minute tuberculatus, pone oculos alate expansw 



marginibus alee antico posticoque sitbcequis, paralldis, margine externo 



excavato, rostro Icevi, cornubus acutis, rectis. Pedes antici subtiliter 



pubescentes, brachio carpoque margines pmtulatis, manu gracili. Pedes 



8 postici longi, graciles, siibtilissime' pubescentes. 



Carapax lyrate, sparingly minute tuberculate, behind the eyes alately 

 produced, anterior and posterior margins of the winged expansion 

 nearly equal and parallel, external margin long and a little concave, 

 the anterior angle acute, posterior subacute. Beak smooth, of mo- 

 derate size, horus acute, straight. Anterior feet inconspicuously 

 pubescent, arm and carpus with pustulate margin, hand thin. 

 Eight posterior feet long, slender, very short pubescent. 



Plate 1, fig. 1 a, male, natural size; b, under view of head, enlarged; 

 <", abdomen, natural size ; d, extremity of posterior pair of legs. 



Puget's Sound, C. Pickering, U. S. Ship Vincennes. 



Near the Hi/as coarctatus in general form. The margin of the 

 upper surface of the carapax posterior to the alate projection, is small 

 tuberculate in a single series. The posterior margin has a small 

 tubercle at middle. The medial region of the carapax is tumid and 

 crossed by a series of small tubercles, and just behind these a tumid 

 tubercle. The post-medial is prominent and has four or five small 

 pustules at top, and either side there passes off obliquely backward 

 across the postero-lateral region a line of small tubercles. The pe- 

 duncle of the eyes has a small tubercle on the anterior side. The 

 exterior maxillipeds are granulous or pustulous. The pterygostomian 

 region has a transverse break in the osseous character of the surface, 

 and is granulous, with the margin entire. Second pair of legs one and 



* The word carapax is not of Latin authority, yet it is so important to the science, 

 that we need make no farther apology for introducing it into that tongue. 



