1881.] NATURAL SCIENCES OF PHLLADELPHIA. 295 



Aual plates numerous. The first intei'radial placed upon the 

 upper sloping sides of the first radials and between the second ; 

 the second series composed of two plates, and there are three in 

 each succeeding series. 



The posterior or anal side is but slightl}' distinct from the other 

 four, but it has generally' three plates in the second, and three or 

 four in each succeeding series. 



Vault very variable, highly elevated to low hemispherical ; the 

 plates comparativelv large and more or less nodose, but sometimes 

 small and scarcely convex ; the interradial regions depressed. 

 Anal aperture subcentral or almost lateral, and extended generally 

 — if not always — into a tube, whose length is unknown. 



Apical dome-plates conspicuous, particularly in species with an 

 excentric amis. 



Column round, composed alternately of longer and shorter 

 joints ; central canal small, round, or obtusely pentagonal. 



Geological Position, etc. — Melocrinus ranges from the Upper 

 Silurian to near the close of the Devonian, and is represented 

 both in America and Europe. 



We place here the following species : — 



^1875. Melocrinus Bainbridgensis Hall (Melocr. — Centrocr. — Bainbridgensis.) 



Gt'i)l. Reji. Ohio Puleon. ii, p. 15S, PI. 13, tigs. 2, 3, above Hurou Shales, 



Devonian. Ross Co., Ohio. 

 *1879. Melocr. Bigsbyi Oehlert. (Clonocr. Bigsbyi.) Bull. Soe. de France (Ser. 



3) vol. vii, p. 4, PI. 2, figs. 2-4. Devonian. St. Germain, France. 

 I?) 1372. Helocr. breviradiatus Hall and Whitfield. Hamilton gr. (We have not 



seen the description.) 

 1S38. Melocr. decadactylus Goldfuss. (Actinocr. decadactylus. Xova Act. Ac. 



Leop. xis, p. 343, PI. 31, fig. 5 ; F. Roemer, Ctenocr. decadactylus, 



Rhein. Uebergangsgeb. p. 61. Grauwacke, near Coblentz, Germ. 

 (Ctenocr. decadactylus Ad. Roemer 1850, Hartzgebirge, p. 2, PI. 1, fig. 1. 



From the Devonian of the Hartz. This is probably different from the 



Coblentz specimens. 

 1S33. Melocr. gibbosus Goldf. Petref. German, i. p. 211, PI. 64, figs. 2: Austin, 1842, 



Ann. and Mag. Xat. Hist, s, p. 109; Schultze, 1867, Mon. Eehin. Kifel 



Kalk, p. 64, Devonian. Eifel, Germ. 

 .%'!. Melocr. Isevis Goldf. (not F. Roemerj. Petref. German.,!, p. 197, PI. 60, fig. 2. 

 (?) 1878. Melocr. grannula*^us Angelin. Icon. Grin. Suec, p. 20, PI. 26, figs. 21 and 



21 a. Upper Silur. Gothland, Sweden. (This is certainly not Melocrinvt 



and we doubt that it is has four basals ; it differs materially in the arrange- 

 ment of the anal plates.) 

 1826. Melocr. hieroglyphicus Goldf. Type of the genus. Petref. German, i, p. 



197, PI. 60, figs. 1 A-E : also Xova Act. Ac Leop., xix, p.339 ; also Lethaea. 



Geogn., i and ii, p. 63 : Roemer, 1855, Lettaea Geogn., PI. 4, figs. 10 a, b, c. 



Rhein, Uebergangsgebirge. Devon. Belgium and Germany. 



