DESCRIPTIONS OF TIIK sl'KCIBS. 229 



l(i). It further resembles these types in having bul one hydrospire-tube on each side 

 nt an ambulacrum (PL XVII. figs. 2-7), although S. Sayi, the typeof the genus, has 

 a much more complex hydrospire-apparatus (tig. 1). 



Locality and Horizon. Foot of Beneachlin, Florence Court, Fermanagh: Carbonic 

 ferous Limestone. (Presented by the Right Hon. the Earl of Enniskillen, D.C.L., 

 F.R.S.) 



Genus CRYPTOBLASTUS, gen. nov. 



I'ciitti/n iii(i/i/is Elliptici (p&rs) , Roemer, Archivf. Naturgesch. 1851, JaErg. xvii. lid. i. p. 391. 

 New Genus (pars), Owen & Shumard, Wisconsin, Iowa, and Minnesota Geol. Report, L852, 



p. 591. 

 Subgenus of Pentremites, Meek & Worthen, Proc. Acad. Nat. Sci. Philad. 18GI, p. 1 I:.'. 

 Ekeacrinus (pars), Shumard, Trans. St. Louis Acad. Sci. 1803, vol. ii. no. 1, p. 111. 

 Granatocrinus (pars), Shumard, ibid. 1 805, vol. ii. no. 2, p. 375. 



Granatocrinusi pars), Meek & Worthen, Report Geol. Survey Illinois, 1860, vol. ii. p. 274. 

 Schizoblastus (pars), E. & C, Ann. & Mag. Nat. Hist. 1882, vol. ix. p. 243. 



Gen. Char. Calyx subglobose, with a flattened or slightly hollowed base. Basal 

 plates small and inconspicuous. Radial plates long and deeply incised. Deltoid 

 plates relatively small and unequally rhombic, the four anterior plates notched by 

 the spiracles near their central ends, and the posterior one pierced by a large anal 

 spiracle. Lancet-plate separated from the radials by an hydrospire-plate, which does 

 not extend above the radio-deltoid suture ; but above this line the lancet-plate meets 

 the deltoids without leaving any hydrospire-pores. 



History. The species which we have taken as the type of this genus {Pentremites 

 melo, O. & S.) was first described, together with Pentremites Norwoodi, by Owen and 

 Shumard '. who regarded it as probable that these two species would together "con- 

 stitute a new genus" of Blastoids. They did not, however, propose any new name 

 for the purpose; and this step was not taken till 1862, when Hall 2 suggested the 

 separation of these species from Pentremites, under the MS. name Granatocrinus, 

 which had been employed by Troost for a Blastoid resembling the two species of 

 Owen and Shumard in the general external characters of the calyx. He pointed out 

 that they differ from Elceacrinus (or, as he called it, Nucleocrinus) in not having the 

 anal interradius conspicuously different from its fellows. About the same time, how- 

 ever, Shumard 3 referred to Elceacrinus all the species which Hall was proposing to 

 place under Granatocrinus; and, so far as Pentremites melo and P. Sayi were con- 

 cerned, there can be no doubt that the arrangement he proposed was better than that 

 suggested by Hall. P. Norwoodi and its European allies, which Shumard proposed 



1 Wisconsin, Iowa, and Minnesota Geol. Eeport, 1852, p. 5'J1. 



- Fifteenth Ann. Rep. New York State Cab. Nat. Hist. 1802, p. 146. 



3 Trans. St. Louis Acad. Sci. 1863, vol. ii. no. 1, p. 112. 



