152 FOSSIL CRINOIDS. 



strata at Buttonmould Knob, Kentucky. A very good calyx was secured in 

 rocks of the same horizon at Lake Valley, New Mexico, which is not distorted, 

 and gives the relative dimensions better than the types, as follows : — 



Height at top of RR 22mm. 



Greatest width at top of BB 31.5 



" at top of RR 28 



Height at top of IBB 7.2 



Width at top of IBB 19 



Width at base 14 



It is therefore a low, spreading calyx, expanding but little to the top of the 

 infrabasals, flaring suddenly and broadly from there to the top of the basals, 

 and thence contracting perceptibly to the distal edge of the radials. The pli- 

 cations in the plates are broad, rounded, and smooth. Radial facets occupying 

 about half the face of the plate, facing obliquely outwards. Primibrachs very 

 short and wide, apparently two or more; one specimen shows two in place, 

 irregular, apparently representing one, with a syzygial distal joint face. Arms 

 unknown, but probably strong, with short and wide brachials. 



Types. I have figured the two original types used by Hall. Figs. 7 and 10 

 were at the time in the collection of Rev. W. H. Barris, now in the Museum of 

 Comparative Zoology, Harvard; Fig. 8 was in that of Dr. Otto Thieme, after- 

 wards acquired by me ; and the other specimens figured are in my collection. 



Horizon and Locality. Lower Burlington Limestone. Burlington, Iowa; 

 Buttonmould Knob, Kentucky; Lake Valley, New Mexico. 



POTERIOCRINTJS DORIS (Hall). 



Plate IV, figs. 1-6. 



1861. Scaphiocrinus doris Hall. Deso. New Crin., 7; Bost. Journ. Nat. Hist., VII, 312. 

 1879. Poleriocrinus doris WArnSMUTH .and Springer, Rev. Pal., I, 111. 



Hall's description is substantially as follows: — 



"Body narrowly calyculate; base truncate, the sides gently expanding to 

 the top of the first radials. Basal plates (IBB) small, about as wide as high. 

 Subradials (BB) proportionally large, the height one fourth greater than the 

 greatest width. First radial plates much smaller than subradials (BB) ; second 

 radials (IBr) elongate, and strongly contracted on the sides just above the middle. 

 Arms bifurcating in the ray divisions on the 8th to 10th brachial ; brachials 

 below a little longer than wide, contracted in the middle and thickened at the 



