58 THE DEVONI\N OF MISSOURI. 



1852-54. Elaeacrinus verneuilii Roemer in Bronn's Lethaea Geogn., Dritte Aufl" 



Theil II, p. 284, 4. f. 10, a and b. 

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

 1859. Elaeacrinus verneuili Bronn, Klassen und Ordn. Thier-Reichs, Bd. i, t. 23, 



f. 5, A-E. 

 1862. Elaeacrinus verneuilii Dujardin and Hupe, Hist. Nat. Zooph. Echinod., p. 100. 

 1865. Elaeacrinus verneuili Shumard, Trans. St. Louis Acad. Sci., II, p. 369. 

 1870. Nucleocrinus verneuilii Billings, Am. Jour. Sci., vol. 50, p. 229, figs. 3-6. 

 1883. Elaeacrinus verneuili E. & C, Ann. & Mag. Nat. Hist., IX, p. 231. 

 1886. Elaeacrinus verneuili E. & C, Cat. Blastoidea Brit. Mus., pp. 216-218, pi. 2, 



fig. 45; pi. 17, fig. 19; pi. 18, figs. 16-18; pi. 19, fig. 7. ■ 

 1889. Nucleocrinus verneuili Miller, North American Geology and Paleontology, p, 



263. 

 1889. Nucleocrinus verneuili Bather, List Blastoidea British Museum (Nat. Hist.). 



p. 22. 

 1902-03. Nucleocrinus verneuili Rowley, Contributions to Indiana Paleontology, I, 



pp. 79-81 and 128-129, pi. 26, figs. 9-15, 18-22; pi. 27, figs. 17-23; pi. 36, figs. 



52-56. 

 1900. Nucleocrinus verneuili Bather, A Treatise on Zoology, III, The Echinoderma, 



p. 88, text fig. 10. 



1909. Nucleocrinus verneuili Wood, U. S. Nat. Mus. Bull. 64, pp. 18-19, pi. 3, figs. 

 7-13. 



1910. Elaeacrinus verneuili Grabau and Shimer, North American Index Fossils, II 

 p. 484, fig. 1796. 



1918. Nucleocrinus verneuili Branson, Geology of Missouri, pp. 100-101, fig. 11. 



Troost's description — "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 subpentagonal form, each of the five angles being elevated and somewhat rounded to 

 receive the five double rows' of pores. Five such plates joined together have a penta- 

 gonal 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 crinoids, 

 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 divi- 

 sions 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." 



