SCYTALOCRINUS. 233 



3. Genus — Scytalocrinus, Wachsmuth and Springer, 1886. 



Sladen 1 founded the genus Dactylocrinus for the Poteriocrinus tenuis of Austin 2 

 (not Miller 3 ) ; and the species S. stadiodactylus described below, which is very 

 similar to that species, seems quite agreeable to his definition. Wachsmuth and 

 Springer, however, statiug that his name had been preoccupied by Quenstedt in 

 1876 for another form, merge Sladen's genus into their own Scytalocrinus,* to 

 which they refer a large number of American fossils. How far our species is 

 congeneric with some or all of these may be doubtful, though in many points it 

 corresponds. It differs from most if not all of them in the very great length 

 and quadrate shape of its arm-joints, and this feature was made by Sladen one of 

 the important characters of his genus. Wachsmuth and Springer explain this 

 away by saying that it simply betokened a young animal. In our case, however, 

 their remark hardly appears applicable ; several of our specimens show the arms, 

 and these are of very great length, and seem to be of sufficiently mature 

 character. 



1. Scytalocrinus stadiodactylus, Whidbome, sp. Plate XXXVI, figs. 2 — 6, 8, 



and Plate XXXVII, fig. 14. 



1886. Poteriocrinus stadiodactylus, Whidbome. Proc. Geol. Assoc, vol. xiv, 



p. 377. 

 1886. — Batheri, ibid., p. 377. 



Description. — Stem apparently long and slender, composed of moderately high, 

 equal or nearly equal columnars. Dorsal cup conical or slightly obconical, 

 moderately deep. Infra-basals five, small, slightly higher than wide, pentagonal. 

 Basals five, apparently large, higher than wide, hexagonal. Radials five ? mode- 

 rately short, truncate above. Primibrachs 5 X 2. Arms ten, very long and 

 slender, composed of very long, narrow, subquadrate plates, and sending out 

 occasionally long slight armlets or pinnules. Anal side with a pentagonal azygous 

 plate, resting on the shoulders of two basals, and bearing an anal piece on its left 

 shoulder level with tbe radials, and another hexagonal anal on its summit; the 

 last two supporting further similar plates, which appear to clothe the lower parts 



1 1877, Sladen, ' Proc. W. Rid. Yorks. Geol. and Polyt. Soe.,' n. s., vol. i, p. (4), pi. x, fig. 2. 



2 1850? Austin, ' Monog. Rec. and Poss. Crinoid.,' p. 83, pi. x, figs. 5 a, b. 



3 1821, J. S. Miller, ' Nat. Hist. Crinoid.,' p. 71, pi. xxii, fig. 2, and pi. xxiv, figs. 1—25. 



* 1879, Wachsmuth and Springer, ' Proc. Acad. Nat. Sci. Philad.,' 1S79, p. 339; and 1886, ibid., 

 1886, pp. 157, 161. 



