BRACHIOPODA. 261 



Genus NEWBERRIA, Hall. 1891.* 



PLATE LXXVm. 



1867. RennKelmria, Meek. Trans. Chicago Acad. Sci., vol. i, pt. i, p. 108, pi. viii, fig. 8 ; pi. xiv, fig. 4. 



1867. Rensselmrlaf Hall. Palaeontology of New York, vol. iv, p. 385, pi. Iviii A, tigs. 9-20. 



1883. Rensselaria, Claypole. Proc. American Philosophiual Society, p. 235. 



1891. Newberria, (Hall) White aves. Contributions to Canadian Palffiontology, vol. i, pt. 3, p. 237, 



pi. XXX, figs. 3, 4, 4 a. 

 1891. Neieberria, Hall. Tenth Ann. Rept. N. Y. State Geologist, pp. 91-99, pis. v, vi. 



Diagnosis. Shell elongate-ovoid, having the general contour and external 

 aspect of Renssel^ria and Amphigenia, but without the strongly radiate-striate 

 surface prevailing in the former genus, and less strongly developed in the lat- 

 ter. The greatest convexity of the valves is in the umbonal region, or above 

 the middle of their length, and in some forms the surface is distinctly flattened 

 over the lateral slopes, leaving the median portion of the valves very promi- 

 nent and sometimes subangular. The cardinal and lateral margins are regular, 

 even and not inflected. 



The pedicle-valve has the rostrum produced and incurved, the apex slightly 

 truncated by the subcircular foramen ; deltidial plates small and obscure. The 

 teeth are comparatively small, projecting forward and gently upward, free at 

 their extremities, and supported by narrow dental plates which join the bottom 

 of the valve above the middle of- its length and are continued forward as 

 slender, widely divergent ridges upon the inner surface, gradually merging 

 into the shell. 



In the bottom of the rostral and umbonal cavity is a broad, usually ill- 

 defined muscular area, from which radiates a series of vascular ridges and 

 depressions extending into the marginal region of the valve. The diductor 

 soars are situated posteriorly and deeply impressed ; between and in front of 

 them is a narrow, elongate adductor scar which is rarely divided medially and 

 often extends forward to, or beyond the center of the valve. On each side of 

 the muscular impression is a thickened area, very narrow at its origin in the 



* On acconnt of similarity to Rbnssblsria in extei-ior form and external shell-markings, the discussion of 

 Nbwberria is introduced here, though we are still in ignorance of the structure of its brachial appaiatus. 

 Further consideration of the Renssbl^kia brachidium and its variations is given with the observations on 

 Cbntbonella and its allies, immediately following. 



