BY R. EXnERIDGE, JUNR., AND JOHN MITCHELL. 713 



moderately tumid ; ocular ridges filamentous, and distinctly 

 tubercled ; genal or palpebral furrows distinct, particularly 

 anteriorly; palpebral lobe very small. Eyes very small, distance 

 between them is to length of the cephalon as 10-7, or a little 

 greater than the distance between a genal spine and the alternate 

 neck spine. Free cheeks of moderate size, moderately tumid, 

 laterally expanded beyond the genal angles, suboval ; borders 

 wide, tumid, each bearing a row of four distinct tubercles on the 

 median line, and at least sixteen stout, horizontal spines, all 

 having a forward direction and apparently increasing in length 

 from front to back to the twelfth, from wdiich each succeeding 

 one is a little shorter; marginal furrow wide and distinct between 

 the facial sutures and genal angles, where they terminate. Genal 

 spines straight, acicular, subslender, and forming an angle of 

 100' with the posterior border of tlie cephalon, or of 120^ with 

 the straight line joining their bases, apparently of moderate 

 length. Facial sutures anteriorly nearly straight, inclining 

 inwards at an angle of 45° and passing out in front of the axial 

 furrows, dividing the greatest width of the cephalon into three 

 equal parts nearly, posteriorly arciform, passing out at the genal 

 angles. Neck furrow wide and shallow, centrally deeper between 

 the false and axial furrows, lateral extensions interrupted by the 

 genal lobe ridges, distinct between the genal lobe and the genal 

 spine ridges. Neck I'ing indistinctly separated from the neck 

 furrow, very moderately arched, curved sharply backward, side 

 lobes small. Occipital spines subslender, projecting backward, 

 and but slightly raised and curved. 



Thorax. — Unknown in a comj)lete state. Pleur:e horizontal, fiat, 

 fulcra very indistinct, ends not deflected nor tliickened, bispinate; 

 posterior spines strong, and projecting from the posterior angles 

 of the pleurae; anterior ones swimmeret-like Or dagger-shajDed, 

 intensely barbed, directed forward and originating in the front 

 angles of the pleurae, so that the two spines on each of the 

 posterior pleurte at least have their points widely divergent from 

 each other. 



Pygidium. — Unknown. 



