168 Description of a new Trilobite. 
the front is rounded and mammillary ; the anterior lateral margin of 
the other lobe on each cheek is lost, but the rest is very perfect. 
The edge nearest the abdomen runs parallel with the articulations 
of the vertebral column, and from its inner edge the front of the 
buckler starts up in high relief. Between the front and the articu- 
lations of the back it is quite narrow, but it swells up and enlarges 
as it proceeds laterally, so as to give to the whole buckler a pente- 
lobate appearance. In the C. variolaris the external angles of the 
buckler have a prolongation down the sides of the abdomen to the 
sixth articulation: our mutilated fragment will not permit a com- 
parison in this particular, as one articulation of the back is all that 
remains. There is no appearance of eyes, though there can be but 
little doubt that these organs will yet be discovered in other speci- 
mens. The breadth of the buckler is one inch and a half; and the 
length, measuring over the front, is the same. 
For this highly interesting species, I am indebted to the kindness 
of Dr. William Blanding, whose indefatigable labors have greatly 
contributed to illustrate several departments of American natural 
history. In a note from that gentleman, which accompanied our fos- 
sil, he remarks, ‘It was obtained from the limestone used in con- 
the national road, the quarry of which is within two miles 
of Springbeld, Ohio.” The limestone is of a light gray color, and 
the fossil is spangled with little crystalline a of that mineral. 
In Parkinson’s Organic Remains, vol. iii. plate 17, figure 16, 
there i is a representation of the anterior coma, of the C. saxsolte 
rts, to which Professor Brongniart refers. The following short ac- 
count of it is given at p. 266, which will enable those who are ¢cu- 
rious, to compare our species with it. “In this animal, the lobular 
divisions seem to have very nearly corresponded with those of the 
Dudley species ; but the structure of the head part differs exceed- 
ingly from every other species. In this fossil, instead of the ap- 
pearance of the distinct parts of a face, there are three large round 
protuberances, the middle being the largest, and all these: protuber- 
ances are closely beset with small tubercular elevations. These pro- 
tuberances occupy nearly the whole space of the head, the eyes being 
placed on the centre of each of the lateral elevations. The matrix of 
this is a fine white limestone, but I am not able to say where it was 
obtained.” 
