152 



PALAEONTOLOGY OF NEW YORK. 



Thorax elongate, rapidly narrowing. Composed of twelve segments. 



Axis broader than either lateral lobe, broadest at the fourth or fifth 

 _inent and tapering rapidly to the pygidium. 



Pleura gently deflected at the fulcra, the segments being conspicuously 

 sulcate. 



Ptgidium imperfectly known, probably very small. 



Surface smooth or minutely granulose. 



Dimensions : 



Body. 



Length 11mm. 



Width 



/ mm. 



Cephalon. 



3.5 mm. 



7 mm. 



Thorax. 



6.5 mm. 

 6 mm. 



Pygiilium. 



1 mm. ? 



2 mm. ? 



Observations. This species approaches Cyphaspis minuscula in the contour 

 and outline of the cephalon, but the much greater width of the axis, more 

 rapidly tapering margins and longer cheek-spines, will serve as distinguishing 

 char act 



A -ingle imperfect individual retaining the parts in juxtaposition, and show- 

 ing the lower surface of the test, and a fragment of the cephalon of another, 

 are all the specimens known of this rare species, and constitute the only repre- 

 sentative of the genus in this horizon. 



Distribution. Lower Helderberg group. Near Clarksville, Albany county ; 

 Schoharie, Schoharie county. 



