1886.] NATURAL SCIENCES OP PHILADELPHIA. 161 



b. With compound brachials. 



*1882. S. briareus (Worthen), Poteriocrinus briareus, Bull, i, III. St. Mus. Nat. 



Hist., p. 12; also Geol. Rep. 111., vii, p. 279, PI. 27, fig. 4. Keokuk limest. 



Keokuk, la., and Bono, Ind. The specific name is given at all places as 



P. briaerius, but evidently was intended for Pot. briareus. 

 1882. S. Burketi ( Worthen). Poteriocrinus Burketi, Bull, i, 111. St. Mus. Nat. Hist., 



p. 5; also Geol. Pi,ep. Illiuuis, vii, p. 270, PI. 28, fig. 8. Keokuk limest. 



Hamilton, 111. 

 *1882. S. coxanus (Worthen), Poteriocrinus coxanus, Bull, i, III. St. Mus. Nat. 



Hist., p. 4; also Geol. Rep. Illinois, vii, p. 269, PI. 27, fig. 1. Keokuk 



limest. Keokuk, Iowa. 

 S. cultidactylus Hall, 1859, was redescribed and figured Geol. Rep. Illinois, 



vii. p. ;iUl, PI. 30, fig. I. 

 18S4. S. extensus W. & Sp., Poteriocrinus asper Worthen, not Pot. (Pachylocr.) 



asper (W. & Sp., Rev. i, p. 116), Bull, i, III. St. Mus. Nat. Hist, p. 11 ; also 



Geol. Rep. Illinois, vii, p. 278, PI. 27, fig. 8. Keokuk limest. Keokuk, Iowa. 

 Poteriocrinus asper being preoccupied, we propose the above name in place 



of it. 

 *18S2. S. iowensis (Worthen), Poteriocrinus iowensis, Bull, i, 111. St. Mus. Nat. 



Hist., p. 6 ; also Geol. Rep. Illinois, vii, p. 272. Keokuk limest. Hamilton, 



111. 

 *1S44. S. macrocbeirus (McCoy), Cyatbocrinus macrocheirus, Synop. Garb. Foss. 



Ireland, PI. 25, figs. 8, 10. Subcarboniferous, Ireland. (This species has 



three brachials.) 

 *187;]. S. montanaensis (Meek), Poteriocrinus montanaensis, Ann. Rep. U. S. Geol. 



Rep. Terr, for 1872, p. 469; also White, 12th Ann. Rep. of the Terr., by 



Hayden, for 1878, p. 128, PI. 3.3, fig. 6 a. Carboniferous. Virginia City 



Montana. 

 *1882. S. nauvooensis (Worthen), Poteriocrinus nauvooensis, Bull, i, III. St. Mus. 



Nat. Hist., p. 13; also Geol. Rep. Illinois, vii, p. 282, PI. 28, fig. 10. 



Keokuk limest. Nauvoo, III. 

 *1882. S. pikensis (Worthen), Zeacrinus pikensis, Bull, i, 111. St. Mus. Nat. Hist., 



p. 304; Geol. Rep. 111., vii, PL 30, fig. 3. Burlington limest. Pike Co., 



Illinois. 

 S1882. S. sculptus (Worthen), Poteriocrinus sculptus, Bull, i, III. St. Mus. Nat. 



Hist., p. 21 ; also Geol. Rep. Illinois, vii, p. 292, PI. 29, fig. 8. Kaskaskia 



gr. Monroe Co., III. 

 (Poteriocrinus subramulosus AVorthen, III. St. Mus. Nat. Hist., p. 14; Geol. 



Rep. Illinois, vii, p. 284, is a synonym of Pot. (Scaphiocrinus) Swallovi 



M. <fc W. This species passes from the upper part of the Upjier Burlington 



into the Keokuk limestone). 



SCYTALOCRINUS W. and Sp., Rev. I, p. 116. 



Syu. Dactilocrinus Sladen, 1877 (not Quensteclt), in pai-t (Ou the genus 

 Poteriocrinus, p. 4). 



General form, including arms, slender, almost cylindrical. 

 Dorsal cup obconical or bell-shaped ; plates strong but not mas- 

 sive, connected by close suture. TJnderbasals well developed, 



