TKOOST'S CRINOIDS OF TENNESSEE E. WOOD. 



35 



projecting above the general level of the body, above it is another complicated pro- 

 jection, having somewhat the appearance of that given by artists of the Roman rostra, 

 which divides the hands [arms] which in this specimen are from 3 to 4 — I think the 

 number must have been four in the living animal. The connecting points of these 

 plates are entirely obliterated by the complicated carving. 



The interscapulars [interbrachials] are also gracefully ornamented— the lower part 

 resembles a coat of arms, the upper part, more projecting, resembles the heraldic 

 ornament which completes the armour. 



The capital integument is composed of polygonal plates being externally globular, 

 and nothing gives a better idea of the term mammillary, because most of these hemis- 

 pherical elevations are surmounted by a papilla. 



The only well defined [anal] aperture that I have seen in the Cupellsecrinites is in 

 this species — it is sub-central and is partly closed by two small tubes geniculately con- 

 nected — whether this is accidentally a post mortem introduction, I can not say, prob- 

 ably the* latter. 



Observations. — This beautiful species of Marsipocrinus is distin- 

 guished from all others of the genus by the elaborate surface orna- 

 ment, the heavy, nodose plates of the tegmen and the four arms to 

 the ray. 



Formation and locality. — Brownsport limestone. Decatur County, 

 Tennessee. 



Cat. No. 39927, U.S.N.M. 



MARSIPOCRINUS CORRUGATUS (Troost). 



Plate 10, fig. 8. 



Cupellsecrinites corrugatus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 



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

 Cupellxcrinus corrugatus Shumard, Trans. Acad. Sci. St. Louis, II, 1866, p. 361 



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



1881, p. 230 (catalogue name). 



The original description is as follows: 



In its general form it resembles the C. Ixvis [C. tennesseensis] but it differs from it 

 in having a pentalobate [?] alimentary aperture [lumen], — the pelvis [base] is not 

 depressed towards the center but rather convex, the costals [radials] are less elevated 

 which give a larger surface to the bottom, and the whole surface is irregularly wrinkled, 

 which wrinkles increase in height towards the lines radiating from the cicatrice left 

 by the column, towards the five angles of the pelvis [base]. The costals [radials] in 

 my specimen are mutilated and the coronal integument entirely destroyed. 



Supplementary description. — Calyx very flat, and consisting of 

 basals, radials, and primibrachs only. The basals extend horizon- 

 tally and have, at the center, a slightly elevated circular disc to 

 which the column is attached. The radials are large, and they form 

 only a slight angle with the basals. Primibrachs very small. All 

 plates of the calyx strongly beveled at the sutures. The entire sur- 

 face is closely set with very irregular, rounded ridges. 



Observations. — This species differs from Marsipocrinus verneuili, its 

 nearest ally, in the beveled sutures and in the surface ridges which 

 are coarser, more numerous, and more irregular. The primibrachs 



