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BULLETIN 64, UNITED STATES NATIONAL MUSEUM. 



ZEACRINUS MAGNOLI^FORMIS (Owen and Norwood). 



Plate 12, figs. 3, 4. 



Cyathocrinus magnoliseformis Owen and Norwood, Res. Protozoic Carb Rocks 

 Kentucky, 1846. 



Zeacrinites magnoliseformis Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 

 1850, p. 61 (nomen nudum); MSS., 1850. 



Zeacrinus magnoliseformis Hall, Rept. Geol. Surv. Iowa, I, Pt. 2, 1858, pp. 544, 

 684. — Wachsmuth and Springer, Rev. Palseocrinoidea, 1, 1879, p. 128 (cata- 

 logue name). — Miller, North Amer. Geol. and Pal., p. 288 (catalogue name). — 

 Keyes, Missouri Geol. Surv., IV, 1894, p. 214.— Weller, Bull. No. 153, 

 U. S. Geol. Surv., 1898, p. 652 (catalogue name). 



Poteriocrinus {Zeacrinus) magnoliseformis Shumard, Trans. Acad. Sci. St. Louis, 

 II, No. 2, 1866, p. 398 (catalogue name). 



The original description by Troost is as follows : 



It is elongated, cylindrical. Pelvis [infrabasal plates] — small pentagonal ? Divided ? 

 [composed of five minute infrabasals]. 



This supposed pelvis lies in a deep cavity and is supported by a cylindrical column 

 having a circular [pentalobate] alimentary canal [lumen]. The cavity being mostly 

 fitted by the column — the form and even the existence of the pelvis [infrabasals] is 

 very uncertain. 



Costals, [radials] five, subtriangular, tumid — superior margin concave, and the lower 

 convex, and being bent inwardly they form the base of the body and the sides of the 

 cavity in the bottom of which, the pelvis? is situated. 



Scapulars [primaxils] five — compressed pentagonal; four of them being placed imme- 

 diately upon the concave surface of the costals [radials] and one upon an interscapular 

 [first primibrach], their superior margin being cuneiform. 



The scapulars [radials] support five arms, upon which follow immediately ten hands, 

 which, after 2 or 3 [3 or 4] joints, have a cuneiform joint, dividing them into two fingers 

 [branches] one of which continues single while the others about 5 joints distant, bi- 

 furcates again, and continues then without any further division. 



I found some mutilated specimens in the Devonian [?] strata in Tennessee. The 

 specimen represented [fig. 3, pi. 12] is from the vicinity of Huntsville, Alabama. The 

 limestone in which it is imbedded, resembles mineralogically that of the vicinity of 

 Nashville which is Silurian; but in Alabama it lies immediately below the Carbon- 

 iferous strata of Mount Sano, which is characterized by Pentremites. 



Observations. — In the Report of the Geological Survey of Iowa (Vol. 

 I, Pt. 2) Hall published Troost' s description of this species as a foot- 

 note in connection with his description of the genus, and later in the 

 same report (p. 684) he published his own detailed description of the 

 species. A diagram of the plates of Troost' s specimen accompanies 

 this description, but no figure of the type was given. 



Formation and locality. — Kaskaskia limestone. Huntsville, Ala- 

 bama; Grayson County, Kentucky; Chester, Illinois. Hall reports 

 the species from Tennessee, but as he describes Troost 's specimen 

 only and gives Tennessee as its locality, the reference is doubtless 

 an error. 



Cat. No. 39936, U.S.N.M. 



