FOSSILS OF THE BURLIXGTON GROUP. 465 



than the column below, and but slightly expanded above 

 to the base, to which they are firmly anchvlosed; in adult 

 specimens perfectly solid, but in young specimens some- 

 times seen to be composed of five or six enlarged, anchy- 

 losed pieces of the column. Ba.se considerably wider than 

 high, with sides expanding upward so as to cause a more 

 or less denned constriction at its connection with the sup- 

 plementary base : more or less pentagonal in outline as seen 

 from below ; basal pieces proper, wider than high, two pen- 

 taironal and one hexagonal in form, the lateral margins 

 being shorter than the others. Radial or fork pieces large, 

 about two-thirds as wide as high, and extremely prominent 

 in the middle: generally a little wider above than below, 

 with a general snboval or nearly oblong outline, the supe- 

 rior lateral angles being, however, obliquely truncated by 

 the interradial and anal pieces, and the lower end a little 

 convex, or obtusely angular in outline at the middle; each 

 with its narrow, pseudo-ambulacral (more properly bra- 

 chial) sinus extending out to its very prominent middle. 

 Anal and interradial pieces rather small, twice as long as 

 wide, distinctly constricted in the middle ; the former more 

 obtusely angular or somewhat rounded, and often convex 

 below ; opening usually regarded as the vent, moderately 

 large, rounded or a little oval, and piercing the anal piece 

 a little below the middle.* Pseudo-ambulacral areas very 

 narrow, with nearly parallel sides, pore pieces (properly 

 recumbent arm pieces) about fifty on each side of the aui- 

 bulacral furrow in a large specimen, all very shallow; lan- 

 cet pieces lanceolate in form, thick, sloping laterally from 

 a very narrow or linear ridge along the middle, which is 

 the only part exposed, and forms the bottom of the arnbu- 

 lacral furrows when the pore pieces are in place; supple- 



* T\~e have several times thought we could see evidences that the anal piece in this species is divided 



into three pieces. That is. first by a transverse suture on each side of the anal opening ; and the inner 



half along the middle by a longitudinal suture. We think we can scarcely be mistaken in regard to 



internal oasts of Granatocrinitt -Voricoodi, showing evidences of this character. Whether or not it 



n the true Ptntrt-mittx. we have been unable to determine. 



