38 ; 
lobate Junates; the front is very convex, and a good 
deal elevated above the cheeks or sides, from which 
it is divided by a deep furrow; on the posterior mar- 
gin of the front on each side, close to the groove there 
is a prominent circular tubercle, before which there 
are three small transverse wrinkles. The cheeks are 
subtriangular; the oculiform tubercle is near the pos- 
terior superior angle, and is only separated from the 
tubercle on the front, by the furrow or groove, so that 
the animal seems to have had double eyes on each 
side; there are two curved lines on each side below 
the eyes, crossed near the front by a deep short canal. 
The middle lobe of the abdomen and tail is rather 
longer than the lateral lobes, and is rounded and very 
prominent throughout. It is composed of 18 articu- 
lations, seven of which appear to belong to the tail; 
it is, however, somewhat difficult to define the length 
of the tail with precision. The costal arches of the 
lateral lobes, particularly those near the tail, are 
bifurcate. Length almost three inches. ) 
The original fossil, from which the cast was taken, 
is in the New York Museum. I am indebted to Mr. 
Rubens Peale, the liberal proprietor of that flourish- 
ing and important institution, not only for the use of 
it in this Monograph, but also for some valuable in- 
formation relating to other species. The precise 
locality of Mr. Peale’s specimen is not known, but 
in the cabinet of J. P. Wetherill, Esq., there is a fine~ 
head of the C. diops which was found in the State of 
Ohio. Both specimens are mineralized by the same 
kind of soft grey coloured limestone—and I have 
