S. I. Smith on American Cirustacea. 151 



The inferior margin of the orbit is finely crenulated, and the crenula 

 tions cease near the external angle, but there is no hiatus. 



The labial border of the epistome has a prominent, triangular tooth 

 in the middle and smaller ones each side ; they all project downward 

 and very slightly forward, and the median one has one or two small 

 denticles toward its base. There is a quite broad, but very short, pro- 

 cess projecting from the upper side of the expiratory canal, nearly in 

 the position of the slender spine in Opisthocera. 



The abdomen is very similar to that of the male Opisthocera just 

 described, except that the first and second segments are scarcely nar- 

 rower than the third. It is remarkably narrow for a female, and the 

 specimen is probably a sterile individual of that sex. 



Epilobocera armata sp. nov. 



Plate V, figure 2. 



The carapax is flattened above and the dorsal surface is neai-ly 

 smooth, but very minutely granulous and punctate with widely scat- 

 tered punctures. The epigastric lobes are just indicated by slight ele- 

 vations and are separated by a very distinct, broad and shallow me- 

 dian sulcus which extends forward and breaks through the superior 

 frontal crest in a smooth sinus. There are no other marks of areola- 

 tion except two minute lunate impressions in the middle of the cara- 

 pax. The superior margin of the front projects slightly beyond the 

 infei'ior one, is nearly straight, as seen from above, but curved down- 

 ward in the middle, as seen in a front view, and is closely armed with 

 conspicuous, rounded tubercles. The inferior margin of the front is 

 straight and its edge is raised into a prominent crest and is distinctly 

 crenulated. The superior margin of the orbit is continuous with the 

 inferior margin of the front and is crenulated like it, and, at the outer 

 angle is armed with one or two spiniform tubercles. The inferior mar- 

 gin of the orbit is finely dentate and is broken beneath the outer angle 

 by a broad, smooth sinus. The antero-lateral margin is separated from 

 the angle of the orbit by a slight hiatus and is armed with sharp, 

 spiniform teeth, which are prominent and slender on the anterior por- 

 tion, but decrease in size posteriorly and are quite small at the broad- 

 est portion of the carapax. The postero-lateral margin is concave in 

 outline, as seen from above, smooth and rounded. 



The labial border of the epistome is divided into three lobes as in 

 the last species. The median lobe is very prominent, projects out- 

 ward nearly as far as the superior crest of the front, is acutely trian- 

 gular and armed with two or three spiniform tubercles on each side, 



