MELOCRINID^. 287 



Dorsal cup about as high as wide ; cross-section subpentangular • the 

 median portions of the basals and costals shghtly elevated 3 their surfaces^ 

 and those of the radials, covered with fine, interrupted stride, and the inter- 

 brachials with elongate tubercles, which at the centre of the plates become 

 obsolete. The suture lines well defined. 



Basals not as large as in some of the other species, forming a shallow 

 basin with obtuse upper angles. Kadials more than twice as large as the 

 costals, slightly spreading ; the upper faces somewhat shorter than the 

 lower First costals hexagonal, their upper sloping faces much shorter than 

 the sloping lower ones ; the second costals smaller than the first, the upper 

 side obtusely angular. Distichals free above the first; the three proximal 

 plates quadrangular, the edges of their upper and lower faces crenulated ; 

 the succeeding three or four plates cuneate, and the plates above interlocking 

 so as to form two rows of arm plates ; the latter covered by two rounded 

 tubercles, transversely arranged, and placed in rows longitudinally. Arms 

 ten, long and rounded. Eegular interbrachials three known; the lower 

 plate twice as large as the two upper; the latter resting against the sides of 

 the second costals, slightly touching the first. All other parts of the species 

 unknown. 



Horizon and Locality. — Shales of the Niagara group ; Lockport, N. Y. 



Bemarks. — We have been unable to trace the type specimen, and our 

 description was made from Hall's figure in the New York Eeport. 



Macrostylocrinus striatus Hall. 

 Plate XXII. Figs, 14a, I, c. 



1863. Hall; Trans. Alb. Inst., Vol. IV., p. 207 (abstr. p. 13). 



1866. Shumaed; Trans. Acad. Sci. St. Louis, Vol. II., p. 361 {Ctenocrims striatus). 



1879. Hall; 28tli Rep. N. Y. State Mus. Nat. Hist. (Museum edit.), p. 129, Plate 13, Kgs. 1-4. 



1881. W. and Sp.; Revision PalEeocr., Part II., p. 103. 



1882. Hall; llth Ann. Rep. Geol. and Nat. Hist., Oliio, p. 257, Plate 12, Pigs. 1-4. 



Calyx to the bases of the arms pyramidal ; the sides shghtly convex ; the 

 fixed brachials formed into broad rounded ridges, which pass up to the arms ; 

 interradial spaces somewhat concave, except at the anal side where the 

 median portion is slightly bulging and angular. Surface of plates covered 

 by fine undulating striae or series of granules, about twelve of which traverse 

 the lower half of the radials to the basals; another set passes up to the 

 costals, and a third and fourth transversely to the sides of adjoining radials. 



