31 



ish limestone. It differs from the C. Blumenbachil, 

 in the form and number of its articulations; in the 

 shape of the head; in having only two flat tubercu- 

 lous elevations on the front; and in other particulars. 

 In the cabinet of the New York Lyceum, and in 

 that of J. P. Wetherill, Esq. there are some examples 

 of this species from the Miami river, near Cincinna- 

 ti, Ohio. I have also seen it from Indiana, in a dark 

 coloured limestone, very much distorted. It has 

 never been found at Trenton falls, or at any other lo- 

 cality, as far as my knowledge extends, which yields 

 the true C. Blumenbachii. 



CALYMENE SELENECEPHALA.* Green. Cast No. 3, 



Clypeo antice rotundato, margine omni valde in- 

 crassato; prominentia frontal! utrinque trituberosa; 

 corpore tuberculato. 



The buckler is regularly lunate; the margin is 

 slightly reflected or raised anteriorly, the posterior 

 edge forms a continuous rim, running nearly parallel 

 with the articulations of the abdomen. The front on 

 each side has one large and two small tubercles, near 

 its superior edge. The oculiferous tubercles on the 

 cheeks are on a line with the lowest frontal tubercle. 

 There are fourteen distinct articulations; but as the 

 tail is mutilated and distorted, the total number of 

 joints cannot, from this specimen, be ascertained. 

 The body appears to have been covered with small 



* From the Greek for " lunate head." 



