344 



Description of several new Trilohites. 



The second series of ribs, which proceed beyond the costal arches 

 of the Cryphseus, we suppose will distinguish it from every other 

 described genus. 



CRYPHiEus Boothii. Green. 



Clypeo antice rotundato ; oculis magnis ; rugis tribus in fronte 

 lateralibus ; articulis septemdecim ; cauda serrata utrinque in denti- 

 bus quinque divisa. 



The general contour of this trilobite is that of an elongated oval; 

 the body projects in high relief above the rock on which it reposes, 

 and its whole length is rather more than two inches. The buckler 

 in our specimen is partly wanting, but the front and one of the 

 cheeks are still in a good state of preservation, and aflbrd a pretty 

 accurate idea of the whole head. 



The front rises above the surface of the cheeks, is rounded and 

 broad at its anterior part and gradually tapers towards the middle 

 lobe of the abdomen. It is distinctly divided from the cheeks, and 

 has three furrows on each side, near its upper edge. The lower 

 furrow is the longest, and is nearly on a line with the inferior edge 

 of the oculiferous tubercles on the cheeks. The middle furrow is 

 the smallest, and appears as a deep depression or pit. The upper 

 furrow is rather above the superior edge of the eyes. The anterior 

 margin of the front is marked by a long curved sulcus, which has 

 the appearance of a lip, as in the Calymene of Blumenbach. 



The cheeks are in the form of spherical triangles. The oculife- 

 rous prominences are close to the front, and are placed just within 

 the internal obtuse angles. The reticulated structure of the eye is 

 quite perfect on the lower portion of the tubercle which still remains. 



We have described the above as the head of our trilobite, though 

 it is detached from the body ; but as it lies in the rock just before ' 

 and in contact with the anterior portions of the animal, there can be 

 little doubt that it once formed a part of it. 



The articulations of the abdomen and tail cannot be distinguished 

 from each other ; seventeen may be readily counted, and though 



