200 Xeiv Species of Fossils front Ohio. 



The species, in its general features, resembles CyatUopliyUum 

 rugosum, Hall, sji., from tliis formation, and may be easily mis- 

 taken for that one, in obscure or imperfect specimens ; but where 

 the internal structure is observable, especially in longitudinal 

 sections of tlie polyps, can be very readily distinguished by the 

 large central space in each polyp, and by the strongly developed 

 transverse tabulfe ; also by the rays not extending to the centre, 

 as in that species and in those of the genus Acerviilaria. "When 

 the coral is weathered, or the substance becomes chalky, so that 

 the polyps are readily separable from each other longitudinally, 

 the appearance very closely resembles that of Cydfliopliylluin 

 rnyosum when in a similar condition, but the interruption of the 

 rays before reaching the centre, and tlie great extent of the 

 tabula?, will then serve to distinguish them. 



Formation and Locality. — In the U])per Helderberg grou]), 

 in Paulding County, Ohio. 



BRACHIOPODA. 

 Streptorliynclius flabelitim, n. sp. 

 Pal. O., Vol. Ill, Plate 2, Figs. 7 and 9. 



Shell below a medium size, semi-circular or semi-ovate in outline, with a 

 straight hinge-line of variable length ; the lateral and front margins are 

 somewhat regularly rounded and, in a protile view, irregularly bi-convex. 

 Ventral valve depressed convex, with a more or less elevated and project- 

 ing but twisted or distorted beak, overhanging a nearly vertical cardinal 

 area of irregular form and width, Avhicli is divided in the middle by a nar- 

 rowly ti'iangular convex deltidium. The dorsal valve is almost regularly 

 semi-circular, very depressed convex, with a slightly more prominent umbo, 

 and is destitute of cardinal area. Surface of the valves marked by from 

 twenty-two to twenty-four strong, rather sharply elevated, radiating pli- 

 cations, Avhich are entirely simple, and separated by broad, concave inter- 

 spaces. The shell is also further marked hj fine, regular, concentric 

 striae of growth, which arch backward in crossing the radii, and may have 

 been sub-lamellose on the external surface, but the examples seen are all 

 exfoliated. 



The species is of a somewhat unusual type, especially in Devo- 

 nian rocks. The dorsal valve seen alone presents so much the 

 appearance of a strongly-marked Aviculopecten, that when first 

 observed it was thought to belong to that genus ; but the venti'al 

 valve, similarly marked, and possessing the characteristically 

 twisted cardinal area and beak with its covered fissure, at once 



