NOETH AMERICAN PALJiONTOLOGY. 247 



Etheridge, Egbert, Jr., and P. Herbert Carpenter— Coutinued. 



mwacriHus, F. Roemer, 1351 (Etueud. Hall, 1862). Typo Fentremitea VerneuiU, 

 Troost. This is purely a Devoniau genus, and appears to be generally dis- 

 tributed tlirongbout that formation in the Uuited States and Canada, but 

 is unknown in rocks of a similar age in Europe. There appear to be no 

 species common to the Lower and Upper Devonian. EUvacrinus VenieiiiU, 

 \aY. pomum, var. nbv., Columbus, Ohio; Coruiferous limestone, Clarke 

 Couuty, Indiana; Upper Helderberg group, Lower Devonian. 



ElcBacrinus sp. ? 



II. Subfamily Schizohlaslidce, E. & C, 1886. 



ScliizoUastus, E. «fe C, 1882. Typo Feiitremites Saiji, Shumard. S. mdonouJes 

 and S. Saiji are limited to the Burlington group. These would be the earli- 

 est species of the genus, unless the Pentrcmitcs Samjisoiii of Hambach form 

 the underlying Chouteau limestone, or Shumard's P. ^lissouriensis should 

 prove to be a Scliizohlasltis. The authors know of no species of it above the 

 Burlington limestone, with the possible exception of Granatocr'unis granu- 

 losus, M. & W., which occurs in the Keokuk limestone of Indiana and Illi- 

 nois. Ouly four species are recognized as belonging certainly to this group, 

 though eight others, it is thought, may belong to it. 



Cryptoblastus, gen. nov. Type Pentremites melo, Owen & Shumard. The genus 

 is exclusively confined to the Subcarboniferous of America, three species 

 belonging to the Burlington limestone and one to the St. Louis; but four 

 species are recognized. 



GranatohJasiicla', E. & C, 1886. Granatocrinus (Troost, 1849; Hall, 1862) 

 (Emend. E. & C, 1882). Type Feniremites ]\^oncoodi, Owen & Shumard. 

 Of the sixteen species which have been described in America G. Norwodi, 

 the type of the genus, is the only one which they can with any certainty 

 refer to this genus ; it occurs in the Burlington limestone. The genus, as 

 now defined, is strictly limited to rocks of Carboniferous age. 



Heieroblastiis,* geu. nov. Type il. Cumberlaudi, six nox. Wentremites coniutus, 

 M. & W., St. Louis limestone, is the only American species referred to this 

 genus. 



Codastcrhlcv, E. & C, 1886. 



I. Subfamily Fhcenoschismidce, E. & C, 1886. 



Codasicr, McCoy, 1849. Type Cadaster Irilohatus, McCoy. 



The authors are prepared to admit five or perhaps nine species of Cadaster 

 though not more, on account of the indefinite manner in which certain so- 

 called Codasters have been described and figured. In Britain there is only 

 one C. trUohatus, the type. Tlie American species differ from the British 

 type in possessing a more elongate form, greater convexity of summit, a 

 narrow base, aud more complex ambulacra. Four of these are well defined, 

 viz : C. alttrnatits, C. graciUs, C. Hindel, aud C. jnjramidatus. Doubtful 

 species are : C. Ameriounus, C. pulchellus, C. Whitei, and Feniremites sub- 

 triincatus. If C. pulchellus, Miller & Dyer, from the Niagara group be 

 rightly so named, this genus has the most extended geological range of all 

 the Blastoidea. Commencing in the Upper Silurian of America, it is well 

 represented both in the Upper Helderberg and in the Hamilton group, of 

 the Devoniau, especially the latter; while the doubtful C. Whitei, Hall, oc- 



. curs in the transition bed between the Upper Burlington and the Keokuk 

 of the Subcarboniferous. The type species (C. <rJ/o&a;«s) is fairly abun- 

 dant in the Carboniferous limestone of Lancashire and Yorkshire, and may- 

 be considered, they suppose, as the last survivor of the genus. 



* " Erepo^, unusual. 



