FOSSILS OF THE BURLINGTON GROUP. 469 



equaling the entire length of the body, and divided almost 

 to their base by the pseudo-anibulacral areas, each with a 

 broad deep sulcus extending up on each side of the pseudo- 

 ambulacral areas, the entire length; while between this 

 sulcus and each lateral margin the surface swells out into 

 a broad rounded ridge, widest near the middle of the body- 

 and narrowing upward and downward, these ridges on each 

 two contiguous pieces being separated by a deeply sulcated 

 suture. Interradial and anal pieces very small, sub trian- 

 gular or cuneate-quadrangular, only about one-sixth the 

 length of the body, measuring over the curve of the sides. 

 Pseudo-ambulacral areas very narrow or sublinear, with 

 sides parallel, equaling the entire length of the body, 

 slightly impressed above, but quite as prominent as the 

 immediate margins of the radial pieces on each side below, 

 if not wider ; pore pieces about fifty on each side of the 

 mesial furrow ; supplementary pore pieces unknown ; lan- 

 cet pieces apparently not exposed externally. Openings of 

 the summit small, but not clearly seen in the specimen. 



Body of the typical specimen O.J:5 inch in hight ; breadth 

 0.5 inch. 



The surface of the typical specimen of this species is not well enough 

 preserved to show fine markings, but another individual of apparently 

 the same species shows the lower half of the radial pieces to be orna- 

 mented with rather tine granules, so as to look like fine transverse 

 stria? under a magnifier, while a few stronger longitudinal stria? are 

 also seen on this part of the body. In this specimen, however, the sur- 

 face of the radial pieces is less convex between their lateral margins 

 and the broad sulcus on each side of the pseudo-ambulacra than in the 

 typical form. 



In form and the narrowness of its pseudo-ambulacra this species re- 

 minds one of G. Sayi, of Shumard, but it is at once distinguished by 

 the very much larger anal and interradial and shorter radial pieces of 

 that species, as well as by the canaliculate character of the sutures be- 

 tween the latter, with a rounded ridge on each side of this suture. In 

 the comparative size of its radial and interradial pieces, as well as in 

 the canaliculated suturesbetween its radial pieces, it agrees more nearly 

 with G. mclo, of O. and S., but is not only distinguished from that spe- 

 cies by its subglobose form, (a little wider than long), and merely even 



