TROOST 's CRINOIDS OF TENNESSEE E. WOOD. 19 



p. 284, pi. iv, figs. lOa-b. — Bronn, Klassen und Ordn. Thier-Reichs, I, 

 1859, pi. xxin, figs. ba-e. — Dujardin and Hupe, Hist. Nat. Zooph. Ech., 

 1862, p. 100.— Shumard, Trans. Acad. Sci. St. Louis, II, 1866, p. 369 (cata- 

 logue name). — Etheridge and Carpenter, Ann. and Mag. Nat. Hist., IX, 

 1883, p. 231; Cat. Blastoidea Brit. Mus., 1886, p. 216. 

 Nucleocrinus verneuili Lyon and Casseday, Proc. Amer. Acad., IV, 1859, p. 295. — 

 Billings, Amer. Journ. Sci. (3), I, 1870, p. 229, figs 3-6.— Miller, North 

 Amer. Geol. and Pal., 1889, p. 263. — Bather, List Blastoidea Brit. Mus. 

 (Nat. Hist.), 1889, p. 22 (catalogue name); A Treatise on Zool., Ill, The 

 Echinoderma, 1900, p. 88, text fig. X. 



The original description by Troost is as follows: 



Pelvis, — or the base of the body — is very complicated in the Olivanites. It is 

 composed of five plates of an irregular form — each has a very elevated ridge running 

 longitudinally over them, this elevated ridge is hollow at the superior margin, in the 

 aperture of which it receives the lower extremity of the double rows of pores or what 

 is generally called ambulacrum, these five plates, joined together have a subpenta- 

 gonal form, each of the five angles being elevated and somewhat rounded to receive 

 the five double rows of pores. Five such plates joined together leave a pentagonal 

 vacuum in its center, and this open place, which I at first considered as a cavity in 

 which a column was inserted, is closed up with numerous small plates forming a kind 

 of mosaic placed at the bottom of the cavity. 



Here the general arrangement of costals, and scapulars as in the generality of cri- 

 noids, terminates. The whole is now composed of a shell on which no suture of 

 junction is perceptible. Consequently it does not belong to the Prentremites in 

 which these divisions are found, and in which the pelvis is divisible into three parts. 



Five double rows of pores, originating at the summit near two small elongated 

 apertures, descending longitudinally terminate in the above mentioned cavity under 

 the elevations of the pelvic plates. These two rows of pores are separated by a narrow 

 strip, or septum, having a longitudinal depression in the middle, and must have 

 answered for the same purpose as the ambulacra in the Pentremites which are also 

 composed of double rows of pores. 



The apertures near the origin of the ambulacra — or double rows of pores — form in 

 the interior a short conical tube, descending a short distance and [it] is not closed — 

 The place where the ambulacra terminate is also open in the interior. 



The intermediate spaces between the ambulacra are superficially divided by 

 longitudinal lines into five parts — the middle part is slightly elevated above the two 

 others, and is more or less longitudinally grooved, while the two following are trans- 

 versely striated. Four of these parts are of equal size — but the fifth is broader and 

 its central part is much more elevated and wider than in the four other divisions, it 

 reaches not the same height and has on its summit a large lanceolate aperture with an 

 elevated border. Its summit is covered with numerous microscopic plates. 



Some imperfect specimens were found in Bedford County, Tennessee. More 

 perfect ones I found at the Falls of the Ohio River [Onondaga limestone]. 



Cat. No. 33075, U.S.N.M. 



NUCLEOCRINUS GLOBOSUS (Troost). 



Plate 3, fig. 6. 



Olivanites globosus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 

 p. 62 (nomen nudum); MSS., 1850.— Hambach, Trans. Acad. Sci. St. Louis, 

 XIII, 1903, p. 50 (catalogue name). 



