288 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



Each line of the transverse sets meets one of the longitudinal lines at right 

 angles or less, and the apices of these angles fall into lines from the centre 

 to the corners of the plates. 



Basals large, forming a flat basin ; column facet small and slightly pro- 

 jecting ; the upper margins distinctly pentangular. Radials large, even for 

 the genus. Costals curved like arm plates ; the first less than one fourth the 

 size of the radials. The first palmar, which bends slightly outward, included 

 in the calyx. Structure of arms unknown, but there were apparently two 

 arms to the ray. Interbrachials in two ranges, composed at the regular 

 sides of one plate each, of which the second is considerably smaller. The 

 anal side, which is much wider, is composed of three plates in the first 

 row ; the median one larger and wedged in between the sloping sides of 

 the radials; the second range consists of five smaller plates, irregularly 

 arranged, and followed by still smaller pieces. 



Horizon and Locality. — Niagara group ; Waldron and Hartsville, Ind. 



Remarks. — This species is allied to M. ornatus, but differs in the propor- 

 tions of the plates and the absence of radial ridges. The specimen figured 

 by Hall in the 20th Eep. of N. Y. State Cabinet on Plate 10, Fig. 7, under 

 M. striatus, seems to us to differ essentially from that species in the propor- 

 tions of the plates, and may even belong to a different genus. 



Macrostylocrinus fasciatus Hall. 

 Plate XXIL Fig. 13, 



1876. Cyathocrinus fasciatus — Hall; Doc. edit. 28tli Rep. N. Y. Stale Museum Nat. Hist., Plate 13, 



JFigs. 5 and 6 (without description). 

 1879. Macrostylocrmus fasciatus — Hall;' Mus. edit, of same Rep., p. 130- and 11th Ann. Rep. Geol. 



and Nat. Hist. Ohio, 1883, p. 258, Plate 13, Pigs. 5 and 6. 



Calyx subovoid ; height to width as ten to seven ; rounded to two thirds 

 the length of the radials, cylindrical above \ arm bases but little projecting ; 

 ventral disk almost flat. Surface of plates densely covered by fine, waving 

 striae, w^hich radiate in fascicles from the basals to a place a little above the 

 centre of the radials, whence other bundles pass out to the interbrachials 

 and adjoining radials. In addition to the striae, the surface is marked by 

 indistinct ridges, which follow the median line of the fascicles, and produce 

 a well defined stellate prominence upon the basal cup and upon each radial 

 and first interbrachial plate. The ridges upon the costals are the most 

 prominent, and increase in width on approaching the arm bases. 



