38 BULLETIN 64, UNITED STATES NATIONAL MUSEUM. 



The original description is as follows : 



Resembles the C. [Marsipocrinus] rosseformis but the interscapulars, [interbrachials] 

 being elevated and consequently the arms more projecting, give it a pentagonal form. 

 The costals [radials] are also more elevated which give the whole a saucer shape ap- 

 pearance. Tlie coronal integument [tegmen] is similar to but less elevated than the 

 C. rosxformis. 



Observations. — This species is most nearly related to Marsipocrinus 

 rosxformis, but differs in its deeper calyx, pentagonal outline, and 

 stronger and more regular surface ridges. The interbrachials in this 

 form are nearly vertical instead of laterally extended as in M. rosx- 

 formis. A faint groove marks the position of the sutures. M. pen- 

 tagonalis is distinguished from M. stellatus by the deeper calyx and 

 stronger surface ornament, and the plates of the tegmen are also 

 more convex. 



Formation and locality. — Brownsport limestone. Perry County, 

 Tennessee. 



Cat. No. 39931, U.S.N.M. 



Subfamily PLATYCRININ^E Bather. 

 Genus PLATYCRINUS Miller. 



PLATYCRINUS HUNTSVILL-fli (Troost) Wachsmuth and Springer. 



Plate 5, figs. 10, 11, 12. 



Platycrinites huntsvillx Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



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

 Platycrinites polydactilus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



p. 62 (nomen nudum). 

 Platycrinus penicillus Meek and Worthen, Proc. Acad. Nat. Sci. Phila., 1860, 



p. 380; Geol. Surv. Illinois, II, 1866, p. 266, pi. xix, figs. 6a-c. 

 Platycrinus plenus Meek and Worthen, Proc. Acad. Nat. Sci. Phila., 1860, 



p. 380; Geol. Surv. Illinois, III, 1866, p. 267, pi. xx, fig. 3. 

 Platycrinus huntsvillx Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, 



p. 388 (catalogue name). — Wachsmuth and Springer, Rev. Palaeocrinoidea, 



II, 1881, p. 234 (catalogue name). — Miller, North Amer. Geol. and Pal., 



1889, p. 271 (catalogue name).— Wachsmuth and Springer, North Amer. 



Crinoidea Camerata, 1897, p. 678, pi. lxxiii, figs. 6, 7a, 7b, 8, 9, 10, 11, 12.— 



Weller, Bull. No. 153, U. S. Geol. Surv. 1898, p. 441 (catalogue name). 

 Platycrinus polydactylus Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, 



p. 389 (catalogue name).— Wachsmuth and Springer, Rev. Palseocrinoidea 



II, 1881, p. 235 (catalogue name). — Miller, North Amer. Geol. and Pal., 



1889, p. 271 (catalogue name). 

 Platycrinus alabamensis Miller, 17th Rep. Geol. Surv. Indiana, 1892, p. 660, 



pi. ix, fig. 5. 



The following is the description of Platycrinus Tiuntsvillse by Troost: 



This species resembles more or less to the Platycrinites Isevis of Miller, but its pelvis 

 [base] differs from that of P. Isevis. The aperture for the insertion of the column is sur- 

 rounded with an elevated circle, from which proceed three elevated ridges. It 

 possesses also a small interscapular [interbrachial] of an irregular form. Its column is 

 cylindrical not elliptical as the P. Isevis. 



