OHI. OU.] 



ECHINODERMA 7 A. 



263 



for receiving the bases of the narrow, 

 elongate ambulacra, and having pro- 

 jecting lips forming a quinquepod; 

 deltoid plates 6, elongate, forming 

 three-fourths of the calyx ; a narrow 

 intercalated plate, on the azygous side, 

 reaches from the aperture to the radial, 

 and divides the deltoid into two nar- 

 row curving plates; sinuses narrow, 

 extending the entire length of the 

 calyx ; ambulacra narrow ; lancet plates 

 long and very narrow ; side plates 

 numerous ; hydrospires pendent, two 

 tubes or elongated sacs on each side of 

 an ambulacrum ; spiracles in five pairs, 

 which notch the deltoid plates; mouth 

 large, covered normally with places; 

 azytrous opening large. Types N. elegans 

 and N. verneuili. 



angulari-", Lyoo, 1857, (Olivanites angu- 

 laris.) Geo. Sur. Ky., vol. 3, p. 492, 

 Ham. Gr. 

 canadens s, Montgomery, 1881, Can. Nat. 



and Geol. Vol. 10, p. 83, Ham. Gr. 

 conradi, Hall, 1862, 15th R~p. N. Y. St. 

 Mus. Nat. Hist., App. 0., p. 121, Up. 

 Held. Gr. 

 elegans, Conrad, 1842, Jour. Acad. Nat. 



Sd. Phil., p. 280, Ham. Gr. 

 hall-ia, syn. for Nucleocrinus elegans. 

 kirkwoodensis, Shumard, 1863, (Eleacri- 

 nus kirkwoodensis,) Trans. St. Louis 

 Acad. Sci., vol. 2, p. 113, St. Louis Gr. 

 lucina, Hall, 1862, 15th Rep. N. Y. St. 

 Mus. Nat. Hist., App. C., p. 120, 



Ham. Gr. 

 meloniformis, 

 Barris, 1883, 

 ( Eleacrinus 

 melon i - 

 f(irmis,)Geo. 

 Sur. 111., vol. 

 7, p. 361, 

 Ham. Gr. 

 obovatus, Bar- 

 r i s , 1883, 

 ( E leacrinus 

 obova t u s , ) 

 Geo. Sur. 

 III., vol. 7, p. 

 358, Ham. 

 Gr. 



verneuili, Troost, 1841, (Pentremites ver- 

 neuili,) 6th Rep. on 

 the Geo. of Tenn., p. 

 14, and Geo. Sur. Ky., 

 vol. 3, p. 488, Up. 

 Held. Gr. 



vern>uili var.pomvm, Eth- 

 eridge & Carpenter, is 

 simply a rounded form 

 very common among 

 other specimens, and 

 without varietal char- FIG. 370. Nncleo- 

 acters. crinusverueuili. 



OHIOCRINUS, Waohsmuth & Springer, 1885, 

 Palaeocrinoidea. pt. 3, p. 208. [Ely. 

 proper name ; krinon, lily.] Plates of 

 calyx arranged as in Heterocnnus ; 



FIG. 369. Nucleocrinus obo- 

 vatus. Cross sectiou of liy- 

 drospires, 2 diaiii. 



arms 10, bearing bifurcating pinnules ; 

 ventral" tube large, having a spiral form 

 somewhat like the cast of a 

 Murchisonia, and covered 

 with hexagonal plates; 

 column pentagonal and pen- 

 tapartite. Type O. laxns. 

 compactns, Meek, 1873, (Hete- 

 rocrinu8constrictU8var.com- 

 pactus,) Ohio Pal., vol. 1, pi. FIG. 371. 

 11, Hud. Riv. Gr. Ohlocrinus 



constrictus, Hall, 1866, (Hete- com P* ctus - 

 rocrinus constrictus,) 24th Rep. N. Y. 



St. Mus. Nat. Hist, p. 



210, Hud. Riv. Gr. 

 laxus, Hall, 1866, (Hete- 



rocrinus laxus,) 24th 



Rep. N. Y. St. Mus. Nat. 



Hist., p. 211, Hud. 



Riv. Gr. 

 cehanus, Ulrich, *1 882 , 



(Heterocrinus cehanus,) 



Jour. Cin. Sue. Nat. 



Hist., vol. 5, p. 175, 



Hud. Riv. Gr. 

 OLIGOPORUS, Meek & Wor- 



then, 1860, Proc. Acad. 

 Nat. Sci. Phil., p. 474. 

 oligos, few; poros, passage.] In 

 form like Melonites, but distinguished 

 by having only four rows of ambula- 

 cral plates, and four double rows of 

 pores in each ambulacral area. Type 

 O. danae. Desor used the name Oligo- 

 pores, in 1858, for a section of the 

 Cidnridae, and Prof. Meek said if desir- 

 able to change Oligoporus, for that 

 reason he would suggest Melonopsis in 

 its place. 



coreyi, Meek & Worthen, 1870, Proc. 

 Acad. Nat. Sci. Phil., p. 34, Keo- 

 kuk Gr. 



FIG. 373. Oligoporus danse ; 2 diam. 



danse, Meek & Worthen, 1860, (Melon- 

 ites danse,) Proc. Acad. Nat. Sci. Phil., 

 p. 397, and Geo. Sur. 111., vol. 2, p. 249, 

 Keokuk Gr. 



nobilis, Meek & Worthen, 1868, Proc. 

 Acad. Nat, Sci. Phil., p. 358, and 

 Geo. Sur. 111., vol. 5, p. 476, Burling- 

 ton Gr. 



parvus. Hambach, 1884, Trans. St. Louis 



Acad. Sri., vol. 4, p. 548, Keokuk Gr. 

 Olivanites, syn. for Nucleocrinus. 



aitgularis, see Nucleocrinus angularis. 



veineuili, see Nucleocrinus verneuili. 



