﻿246 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 47 



the elongated pores being continuous across the suture between the 

 two plates on which each rhomb is situated." He also calls atten- 

 tion to the fact that one arm is shorter than the others. The holo- 

 type, now preserved in the collections of the Geological Survey of 

 ( 'anada, and kindly loaned to the writer by Professor Whiteaves, 

 shows that the character of the rhombs and the number of arms 

 arc those of Callocystites and not of Apiocystitcs. Moreover, the 

 other Canadian specimens studied by the writer come from the iden- 

 tical locality that furnished Billings's type. Both were collected by 

 Mr. J. Pettit. 



Ringueberg's C. tripectinatus is also a 5-armed individual, the rays 

 having unequal length. Two of the rays are " slightly bifid at their 

 lower extremity." His differential specific character is the " paired 

 hydrospires " in contradistinction to the separated ones in C. jewettii. 

 As he does not mention Billings's species Apiocystitcs canadensis, he 

 was probably unaware of the identical type of pectinirhomb in that 

 form. 



Formation and locality. — Rochester shales at Grimsby, Ontario. 

 Three specimens, collected by Mr. J. Pettit and now in Dr. Walker's 

 collection. Another specimen was found near Lockport, New York, 

 by Mr. Ringueberg. 



Cat. number 35.135, U. S. N. M. Presented by Dr. Walker. 



Ccelocystis Schuchert 



Hemicosmites Hall (not von Buch), Twentieth Rep. N. Y. State Cab. 



Nat. Hist., rev. ed, 1868 [1870], p. 359- 

 Sphcerocystites Jaekel (not Hall), Stammesgeschichte der Pelmatozoen. 



Berlin, 1, 1899, p. 289, fig. 63; also p. 307. 

 Ccelocystis Schuchert, Araer. Geol., xxxn, 1903, p. 234. 

 Until recently, Sphcerocystites seems to have been based on a single 

 example— the holotype of S. miiltifasciatits. As this specimen did 

 not permit Hall to make out the thecal structure, Jaekel gave the plate 

 formula for the genus, basing it on S\ doioiniticus Jaekel ,= Hemi- 

 cosmites subglobosus Hall. In the present work the plate formula 

 for Sphcerocystites is based on the genotype S. miiltifasciatits, and 

 this study has shown that Jaekel's type belongs to another and more 

 primitive genus. For this reason the Niagaran form is here distin- 

 guished under the genus Coalocystis, the name having reference to 

 the deeply invaginated base of the theca. 



Hemicosmites is a quite different form, as the plate formula is 

 4 _l. 6 -f 9 + 9, anal area 7, 8, and 13 (see Bather, Treatise on 

 Zoology, in. Echinoderma, London. [900, p. 68. fig. 3). 



