FOSSILS OF THE BURLINGTON GROUP. 381 



CAXALICULATUS, M. and TV. 



PI. 6, Fig. 4. 

 Dorycrinus canaliculatux. MEEK and WORTHBN. Proceed. Acad. Xat. Sci., Phila., 1869, p. 166. 



BODY under medium size, cup-shaped below the arms, 

 rather rapidly expanding from the lower margins of the 

 first radials to the arm bases. Base extremely short, its 

 entire hight merely consisting of the thickness of the plates, 

 siibhexagonal in outline, with small lateral notches at the 

 sutures, scarcely projecting below the first radial and first 

 anal piece ; facet for the attachment of the column occu- 

 pying about half the breadth of the base, round and rather 

 deeply impressed. First radial plates about once and a 

 half as wide as high, all very nearly hexagonal, there being 

 scarcely any perceptible angle at the middle of those over 

 the sutures of the base. Second radials scarcely half as 

 large as the first, about once and a half as wide as long, 

 and presenting the usual quadrangular outline. Third 

 radials a little wider and shorter than the second, pentago- 

 nal in form, and bearing on their upper sloping sides, in 

 the posterior rays, two slightly smaller secondary radials, 

 each of which supports two brachial pieces, thus giving 

 origin to four arm openings to each of these two rays; 

 while in the anterior ray one side of the third radial merely 

 bears a series of brachial pieces leading to an arm, and its 

 other side a tertiary radial, supporting two brachial pieces, 

 thus making three arms to this ray. In both anterior 

 lateral rays each third radial bears on each side two bra- 

 chial pieces in direct succession, making only two arm 

 openings to each of these rays, or fifteen to the entire 

 series.* 



Anal pieces about eight, below the horizon of the arm 

 openings : first one as wide as the first radials, and a little 

 longer, heptagonal in form, and bearing three smaller pieer< 

 in the second range, above Avhich there are five smaller 



*Sixteen is probably the normal number. 



