FOSSILS OF THE WKMNdTON (iROUP. 453 



vated. Second radials small, but generally quite filling, 

 or sometimes a little more than filling the sinuses in which 

 they rest, subtrigonal or pentagonal in form, with very short, 

 lateral margins, directed upward and a little outward. 



Divisions of the rays, after the first bifurcation on the 

 second radial pieces, each composed first of two pieces in 

 direct succession, the second of which is an axillary piece, 

 and bears an arm on its outer sloping side, while on its 

 inner it supports two pieces in direct succession, the second 

 of which is an axillary piece, and gives origin to two arms, 

 thus making three arms to each of the two main divisions 

 of each ray. or thirty to the whole series. 



Arms rather slender, rounded on the dorsal side, and 

 scarcely thicker in the middle than below; each composed 

 near their bases of five or six wedge-formed pieces extend- 

 ing entirely across, but a little above they soon pass into a 

 double alternating series of pieces nearly as long as wide; 

 piiinulap nearly or quite in contact with each other and 

 composed of pieces three or four times as long as thick. 

 Interradial pieces of moderate si/e. strongly incurved, and 

 wider below than above; anal piece larger than the inter- 

 radials, wider than long, hexagonal in form, and not in- 

 curved. Vault depressed, convex, or but little elevated, 

 composed of few tuberculiform pieces, about five of the 

 central ones of which are larger than the others, and occupy 

 nearly the whole area. Opening lateral, and either raised 

 iuto a small protuberance, or more probably extended so 

 as to become proboscidiform. Surface merely finely gran- 

 ular. 



Hight of body to top of first radial pieces, 0.38 inch ; 

 breadth at same point, 0.66 inch. 



This species is more nearly allied to P incomptus, of White, than to any 

 of the other smooth species known from the Burlington rocks. In form 

 and the general appearance of the body, these two species are so very 

 similar, that it would probably in some eases be very difficult to distin- 

 guish them without seeing the other parts. Dr. WHITE'S species, how- 



