CRUSTACEA. 



Cephalon semi-elliptical in outline, slightly produced anteriorly ; border broad, 

 depressed by the wide marginal sulcus and strongly reflexed : produced at 

 the genal angles into stout spines which extend as far as the fourth thoracic 

 segment. Length to width as 1 to 2. 



Facial Sutures normal; points of intersection with the frontal margin 

 relatively distant. 



Glabella sub-triangular or conate : convex, tumid anteriorly and elevated 

 along the median line; abruptly depressed toward the frontal border. Length 

 equal to five-sixths the length of the cephalon; width at the base more than 

 one-third the width of the same. Lateral glabellar furrows in four pairs; 

 first pair short, transverse, situated at one-third the length of the glabella 

 from the anterior extremity: second pair longer, inclined slightly backward ; 

 third pair still longer and with a greater posterior inclination ; fourth pair 

 longest and deepest, each furrow curving to meet the occipital furrow at 

 one-third the distance across the base of the glabella; accessory furrows 

 - conspicuous, oblique. The lobes of the glabella increase in size backward, 

 the fourth pair being large and obliquely sub-triangular. They are followed 

 behind by large, transverse, occipital lobes, which are distinctly circumscribed 

 by the bifurcated occipital furrow. Occipital furrow shallow on the axis, 

 increasing in width and depth upon the checks: occipital ring broad, flat, 

 depressed below the glabella, and narrowing on the cheeks. 



Cheeks convex about the orbital node, slightly flattened above, abruptly 

 depressed to the broad marginal sulcus and recurved upon the margin. The 

 marginal sulcus extends into the cheek-spines making them concave. 



Eyes lunate, relatively small and very closely appressed to the glabella. 

 Palpebral sulcus shallow and elevated. 



Thorax sub-rectangular, lateral margins gently converging posteriorly : sub- 

 equally trilobate. 



Axis convex, prominent, widest at about the fourth segment, with margins 

 slightly rounding thence to the pygidium. Segments transverse, Hat and 

 thin. 



