1886.] NATURAL SCIENCES OP PHILADELPHIA. 189 



The underbasals -were united by a common suture, the lines of 

 which in the adult Crinoid are completely obliterated. The basals 

 possess, among each other, and where they meet the underbasals 

 and radials, ramifying furrows along their faces, which, together 

 with similar furrows on apposed faces, form tunneled passages, 

 probably containing ligament ; the lateral faces of the radials, 

 however, are excavated for fossae. 



Geological Position, etc. Restricted, so far as known, to the 

 Kaskaskia group of America. 



The following species have been described : 



1873. Agassizocrinus carbonarius "Worthen, Geol. Kep, III., v, p. 566, PL 24, fig. 4, 

 Coal measures. Shelby Co., III. 



1873. A. cliesterensis Worthen, Geol. Rep. 111., v, p. 558, PI, 21, fig. 9. Kaskaskia 

 gr. Chester, 111. 



1851. A. conicus Owen and Shum., Journ. Acad. Nat. Sci. Phila. (n. ser.), vol. ii, p. 

 93, PI. xi, fig. 6. Geol. Rep. Iowa, Wise, and Wmn., p. 697, PI. 5 b, fig. 6. 

 Meek and Worthen, 1873, Geol. Rep. Illinois, PI. 21, fig. 8. Kaskaskia 

 limest. Chester, Illinois. 



1858. A. constrictus Hall, Geol. Rep. Iowa, vol. i, p. 687, PI. 25, fig. 10. Kaskaskia 

 gr. Chester, Illinois. 



1850. A, dactyliformis Troost, Type of the genus. List Crin. Tenn. Cainbr. Meet., 

 p. 6U; Shum. 1853, Marcy's Rep. Red River, p. 173. Hall 1858, Geol. Rep. 

 Iowa, vol. i, p. 685, with diagram. Kaskaskia gr. Chester, III., and Crit- 

 tenden Co., Ky. 



1S58. A gibbosus Hall, Geol. Rep. Iowa, vol. i, p. 686, PL 25, fig. 6. Worthen 1873, 

 Geol. Rep. 111., v, PL 21, fig. 11. Kaskaskia gr. Chester, IlL 

 A. gracilis Troost is a catalogue name. 

 *1855. A. laevis (Roemer), A.stylocrinus laevis (Second type of the genus), Leth. 



Geogn. (Ausg. 3), p. 229, PL 4, fig. 13. Kaskaskia gr. 

 *1852. A. occidentalis Owen and Shum. (Poteriocrinus oocidentalis), Journ. Acad. 

 Nat. Sci. Phila. (n. ser), vol. ii, p. 92, PL xi, tig. 6; also Geol. Surv. of 

 Iowa, Wise, and Minnes., p. 596, PL v 6, fig. 4. (Probably a young speci- 

 men of A, gibbosus Hall). Kaskaskia gr. Chester, Illinois. 

 A. pantagonus Worthen, Geol. Rep. III., v, p. 556, PL 21, fig. 10. Kaskaskia 

 gr. Chester, Illinois. 



1862. A. tumidus Owen and Shum., Journ. Acnd. Nat. Sci. Phila., vol. ii, p. 90, PL 

 xi, fig. 3 ; also 1852, Geol. Surv. of luwa. Wise, and Mianes., p. 595, PL v b, 

 fig. 3. Kaskaskia gr. Chester, Illinois. 



(?) EDRIOCRINTJS Hall. 



1859. Hall, Pal. Rep. N. York, vol. ill, pp. 199 and 143. 



1832. Hall, loth Kep. N. York. St C.ib. Nat. Hist., p. 115. 



183S. Meek au I Worthen, Gaol. Rip. Illluois, vol. ill, p. 119. 



1879. Zittel, Handb. d. Palaeontologie, i, p. 350. 



1883. P. H. Carpenter, Ann and Ma^^ Nat. Hist. (May, 1883), p. 333. 



Edriocrinas led a life similar to that of Agassizocrinus, being 

 attached in its larval state, and free-floating in the adult. It 



