466 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



Dorycrinus subturbinatus (M. and w.). 

 Plate XML Figs. 10a, h. 



1800. Actmocrimis (^Amplioracritms) subturbinatus — Meek and Wokthex ; Proceed. Acad. Nat. Sci. 



Phila., p. 3S8. 

 1866. Amfhoracrinus subturbinatus — M. and W. ; Geol. Hep. Illiuois, Vol. II,, p. 212, Plate 15, Figs. 



4«, b. 

 1873. Dorycrinus subturbinatus — M. and W. ; Ibid., Vol. V., p. 380. 

 1881. Dorycrinus subturbinatus — W. aud Sp. ; Kevisiou Palceocr., Part XL, p. 179. 



A small species, in the form of tlie calyx resembling D. mississippieiisis. 

 Dorsal cup broadly obconical ; the sides straight from the colunm to the 

 arm bases, with a shallow depression at the interradial spaces ; the rays not 

 so distinctly lobed as usual in this genus ; plates fiat, and devoid of orna- 

 mentation or other markings. 



Basals small, forming an obconical cup, rounded at the lower end ; the 

 column facet narrow, occupying the full width of the lower face. Eadials 

 a little wider than long, fully twice as wide as both costals together, the 

 upper face concave. First costals quadrangular, as wide again as long. 

 Second costals wider than the first, generally quadrangular, exceptionally 

 hexangular or heptangular. They support in the anterior and posterior 

 rays an axillary distichal, and this, in turn, a small palmar from each side ; 

 while the antero-lateral rays have two distichals and no palmars. Inter- 

 brachials one and two ; the first large, as wide as long, the two others as 

 long but one half narrower. Anal side very wide, a little bulging at the 

 arm regions, incurving above, and elevated at the median line. It consists 

 of three hexagonal anal plates, the first as large as the radials but somewhat 

 longer and narrower; the other two decrease in size upward, and are fol- 

 lowed by a number of smaller plates arranged around the anus. The anals 

 from the second plate up sustain at each side an interbrachial, the lower 

 pair of which being nearly as large as the corresponding single plate of 

 the regular sides, the upper ones being much smaller. Ventral disk de- 

 pressed-convex, somewhat inflated along the sides, flattened on top. The 

 surface is covered with six spines, which are short, coming rapidly to a point. 

 The middle spine occupies nearly the centre of the upper face, the lateral 

 ones are placed almost vertically to the arm bases. Arrangement of orals 

 and radial plates as in the preceding species. Anus at midway between the 

 posterior oral and the base of the arms, directed laterally. 



