WHITEAV6S.] FOSSILS OF HAMILTON FORMATION OF ONTARIO. 369 



Ollacrinus spiniycrii^s, Waohsinuth and Springer. 1881. Rev. PaliEoorinoidea, pt. 2, 

 p. 219. 

 " " Whiteaves. 1887. This volume, pt. 2, (advance sheets) p. 103 ; 



and (1889) pi. 13, figs. 4, 4, u.-h. 

 Cfonmsteroidor.rinus spinigerwi, S. A. Miller. 1889. N. Amer. VmA. and Pateont., 



p. 250. 

 Cilhertsocrinns spinfjcrus, Wachsni\ith and Springer. 1897. N. Amer. Crinoidea Ca- 

 merata, vol. I., p. 247, pi. 15, figs. 3, a-c. 



In the volume last cited, the generic name Ollacrinus (Cumberland, 

 1826) is rejected for this and other species, on the ground that it "cannot 

 be looked upon as lawfully published," and the name Gilbertsocrinus 

 (Phillips, 1836) adopted instead, 



DoLATOCRiNus CANADENSIS, Whiteaves. 



Dolatocrinus Canadensis, Wix\te&\f.s. 1887. This vol., pt. 2, (advance sheets) p. 99 ; & 

 (1889) pi. 12, tigs. 3 &3o. 

 " " Wachsmnth and Springer. 1897. N. Am. Crinoidea Camerata, 



vol. I., p. 315, pi. 2o, figs. 7, a-h. 



This crinoid, which has three primary arms in each ray, has recently ■ 

 been redescribed and refigured in the beautifully illustrated monograph 

 by Wachsmuth and Springer quoted above. The species would appear to 

 be rare, as the specimen from Thedford figured on Plate 12 of this volume 

 is still the only one that the writer has seen. 



DOLATOCEINUS SUBACULEATUS. (N. Sp. ) 



Plate 48, tigs. 6, 6 a, and 6 h. 



Calyx depressed hemispherical, broader than high and flattened below, 

 rather small for the genus, not much exceeding fifteen millimetres in 

 maximum breadth in the few specimens that the writer has seen. Pri- 

 mary arms in each ray, two. Basals and lower halves of the radials deeply 

 incurved, like those of D. lacus, Lyon (as recently described by Wach- 

 smuth and Springer on pages 311 and 312 of the first volume of their 

 monograph of the "North American Crinoidea Camerata"), and form- 

 ed, as in that species, into an " inverted funnel-shaped cavity which is 

 wider than the column, the latter touching only the bottom part." 

 Around the base there is a large pentagon, the outer boundary of which 

 is formed by a narrow continuous ridge which connects the radials late- 

 rally. Each of the angles of this pentagon is intersected vertically by a 

 linear ridge, which occupies the middle of each ray, and each side of this 

 pentagon forms the ba.se of a triangle, the apex of which is the centre of 

 the first interbrachial. The linear ridge along the median line of each 

 ray is prominent, acute, and bears two laterally compressed, rather 



