﻿LEPTiENA. 



87 



Leptvena (?) laticosta, Conrad. PI. XVII, figs. 1, 2, 3. 



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Leptjexa laticosta, Conrad; — de Verneuil, Bull. Soc. Geol. France, 2nd series, vol. iv, 

 p. 705, 1847. 



— — Sc/tnur, in v. Meyer und Dunkcr's Palseontographica, vol. iii,p. 



220, pi. xl, fig. 2, 1853. 

 Stropiiomena laticosta, Sandberyer. Die Brachiopoden des Kheinischen Schichten- 



systems in Nassau, p. 66, pi. xxxiv, fig. 8, 1855. 



Spec. Char. Transversely semicircular, and slightly indented in front ; wider than long ; 

 hinge-line a little less than the width of the shell ; ventral valve moderately convex ; 

 cardinal line almost straight ; beak small, and but slightly produced ; surface marked by 

 about thirty-one or more simple radiating ribs, the central one being wider than any of 

 the others ; area narrow, and divided in the middle by a small fissure arched over by a 

 pseudo-deltidiuni ; dorsal valve slightly convex at the beak, and gently concave near the 

 margin ; exterior surface ornamented by a similar number of ribs as in the opposite valve, 

 but along the centre there exists a wider and deeper furrow, which corresponds with the 

 median rib of the opposite valve ; area linear. Proportions variable — 

 Length 9, width 12 lines. 



Oh. Of this species I am acquainted only with impressions of the exterior and 

 internal casts which occur at Meadfoot, near Torquay, as well as in the brown sandy 

 grits or slates of Looe, in Cornwall. The muscular and other impressions on the surface of 

 the internal casts were not sufficiently defined to admit of an accurate description, and I am 

 consequently uncertain whether this species should be retained in the sub-genus Leptcena. 



On the Continent, and especially in the Eifel, where it likewise occurs in the state of 

 impressions and internal casts, the shell appears to have attained larger proportions. 

 M. de Verneuil observes, in his paper already mentioned, that this species in America is 

 found in the Hamilton group of Hamilton County, New York ; also at Daun, in the 

 lower schists or limestone of the Eifel, as well as in the Devonian limestone of Gahard, 

 in Brittany. 



Germs Orthis, Dolman, 

 Orthis striatula, Schloth. PI. XVII, figs. 4 — 7. 



. Hysterolites, LinncBus. Mus. Tessiuianum, p. 90, pi. v, fig. 2, A, B, C, D, 1755; 



id. Baumer — Naturges. des Mineralsreiclies, 2nd part, fig. 28, 1764; 

 id. Walch and Knorr. — Die Naturg. der Verst., pi. B, figs. 5, 6, 1768, 

 and of several other old authors who designated internal casts of 

 0. striatula by the term Hysterolites. 



