CONTRIBUTIONS TO PALEONTOLOGY. 139 



CACABOCRINUS LIRATUS ( n. s.). 



Body large, oblate or depressed-spheroidal, somewhat lobed at the 

 top of the calyx, and on the summit by the arm-bases : base flat- 

 tened. Basal plates depressed for the column-facet, which is about 

 one-half their diameter; the depression bounded by an elevated 

 rounded rim. First radial plates large. Second radials about half 

 as large as the first, broad, quadrangular. Third radials about 

 equal to or a little smaller than the second, much wider than 

 high, pentangular; supporting upon each upper margin two large 

 supraradial plates, one above the other : upon the upper one 

 rests the first arm-plate. 



Interradial series consisting of two or more plates; the first one 

 very large, somewhat elongate, nine-sided ; the second resting 

 upon the first, irregular, wider below, and reaching to the centre 

 of the arm-bases : sometimes there is an irregular plate on one or 

 both sides of this second interradial, between it and the second 

 supraradial. Dome moderately convex, strongly lobed; the lobes 

 corresponding with the rays, composed of rather large plates, 

 some of them subspinose, with a subcentral proboscis of medium 

 strength. 



Surface of calyx-plates marked by several parallel sets of strong 

 elevated striae, the longest radiating from the centre, where they 

 form a low angular node : they unite with those from adjoining 

 plates, crossing the sutures at right angles. On different parts, 

 these sets vary from two to five or six. A stronger ridge passes 

 along the centre of each ray, rising from the edge of the central 

 depression of the basal plates, bifurcating on the third radial, and 

 extending to the arm-bases. 



Arms two from each ray at their origin, with strong bases, composed 

 of a double series of short interlocking plates. 



Geological formation and locality. In the shales of the Hamilton group: 

 at several localities in Western New- York. C. A. White, collector. 



CACABOCRINUS LIRATUS, var. MULTILIRA. 



This form is similar to the preceding, but more oblate, with more 

 spreading cup and proportionally larger column : the depression 

 in the basal plates is less, and the surface-markings more evenly 

 developed and more numerous, having from three or four to nine 

 striae on each face of the plate, and the small triangular areas 

 within the sets marked by distinct granules. The ridges traversing 



