DESCRIPTIONS OF THE SPECIES. 278 



Pentremites caryophyllatus, de Koninck. Carboniferous Limestone ; Belgium. 

 [ Pentremites [CodasterV) /\'< nt nc/,yi nsis,S\mnvdnl. Subcarboniferous; Kentucky. 

 Phcenoschisma nobile, E. & C. Lower Devonian; Leon, Spain. 

 Phcenoschisma Vemeuili, E. & C. Lower Devonian ; Leon & Asturias, Spain. 



We have placed Pentremites Kentuchyensis, Shumard \ in Phcenoschisma rather 

 than in Codaster, to which he subsequently referred it 2 , on account of the narrow 

 and linear form of the ambulacra, which are closely similar to those of P. nobile and 

 P. Vemeuili (PI. XL fig. 4; PI. XIV. fig. 9), and somewhat different from those of 

 Codaster. 



Mr. Wachsmuth has also sent us two species from New Mexico which he will 

 himself describe eventually, so that the occurrence of the genus in America rests on 

 other evidence than that of Shumard's Pentremites Kentuckyensis. 



Distribution. The earliest known species of Phcenoschisma are P. Archiaci and 

 P. Vemeuili, which occur in the Calcaire de Ferrones in the Lower Devonian of 

 Spain. Like Pentremitidea Paillettei, they both pass up into the Calcaire d'Arnao, 

 where P. nobile also occurs. The Carboniferous Limestone Series of England, Scot- 

 land, and Belgium, each contains one species, and there would appear to be three 

 others in rocks of corresponding age in America, so that the genus has a compara- 

 tively extensive range, both in space and in time. 



Type. Pentatrematites acuta, G. B. Sby. 



1. SPECIES FROM THE DEVONIAN. 



Phcenoschisma Verneuili, E. & C. 

 (PL X. fig. 18 ; PI. XL figs. 5, 6 ; PL XIV. figs. 8, 9.) 

 Ptmenoschisma Vemeuili, E. & C, Ann. & Mag. Nat. Hist. 1882, vol. ix. p. 230. 

 Sp. Char. Calyx elongately pyramidal ; base sharp and pointed ; summit hollow, 

 excavated in the direction of the rays ; the ambulacra are separated by strong inter- 

 radial processes, each of which is formed by the union of the adjacent limbs of two 

 contiguous radials ; section distinctly pentagonal at the distal ends of the ambulacra. 

 Basal plates forming an elongated cup, about two thirds the length of the radials, 

 and a little longer than the bodies of those plates. Radial plates large and arched ; 

 limbs long and projecting above the summit, but those of the anal interradius are 

 flattened or depressed ; sinuses very wide and deep, with high sloping sides ; lips 

 prominent, with three folds diverging downwards from each. The anal deltoid is 

 diamond-shaped. Ambulacra linear, scarcely increasing in width ; lancet-plate 

 narrow, entirely concealed ; side plates from twenty to twenty-live, apparently oblong; 



1 Trans. St. Louis Acad. Sci. 1858, vol. i. no. 2, p. 239, pi. ix. fig. 5. 

 2 Ibid. 1865, vol. ii. no. 2, p. 359. 



2N 



