13 
can scarcely be discerned ; in some of the fragments 
of the buckler which I have examined, I oct xt 
discover them at all. The abdomen is composed of 
twelve articulations ; the costal arches or ribs are 
marked on their upper surface with a groove, and they 
terminate in free angular extremities. ‘The middle 
lobe of the back is scarcely tapering, till within a few 
articulations of the extremity of the tail. The. tail is 
quite short, rounded, and without the membranaceous 
expansion so common in the Asaphs ; indeed this spe- 
cies forms an inosculating link between the genus 
Calymene and Asaphus. 
I am indebted to the kindness of Dr. J. KE. Dekay 
for this species.- It occurs in a loose, bituminous, 
shaly limestone, full of iron pyrites. It was found in 
the state of New York, probably at Newport. The 
whole animal is very much depressed ; and the rock 
is completely filled with its mutilated remains, some 
of which are still covered with the original crusta- 
ceous shell. wy ae 
The cast we have given to illustrate this species 
represents two distinct animals, one directly over the 
other ; so that the buckler and some of the vertebre 
of one, appears at first sight to constitute a part of 
_the abdomen and tail of the other. kg 
2 
