CAMAROPHORELLA 459 



margins of the Camarophcria cruralium, and become attached to the inner 

 surface of the valve, so forming the pair of slender finger-like cavities 

 lying on either side of the median septum. In addition to the presence 

 of a spondylium in the pedicle valve, the support of the jugum by the 

 high median septum of the brachial valve is a character which has not 

 heretofore been recognized in the atheroid shells. The presence of a 

 spiral brachidium has never been observed in the Kinderhook species 

 here recorded, but in C. lenticularis the characters of the septa observed 

 in the internal casts are so entirely like those of the Ohio shells in which 

 the spires have been observed, that their reference to the same genus 

 seems to be well founded. 



CAMAROPHORELLA LENTICULARIS (White and Whitfield) 

 Plate LXXXII, Figs. 61-63 



1862. Pentamerus lenticularis AVhite and Whitfield, Proc. Boston Soc. Nat. 



Hist., vol. 8, p. 295. 

 1865. Pantamerus lenticularis Winchell, Proc. Acad. Nat. Sci. Phil., p. 117. 



1894. Camarophorella lenticularis Hall and Clarke, Int. to Study of 



Brach., pt. 2, pi. 45, figs. 5-6. 



1895. Camarophorella lenticularis Hall and Clarke, Pal. N. Y., vol. 8, pt. 2, 



pi. 62, figs. 46-48. 

 1901. Camarophorella lenticularis Weller, Trans St. Louis Aead. Sci., 



vol. 11, p. 162, pi. 14, figs. 11-13. 

 1908. Camarophorella lenticularis Hyde, Proc. Boston Soc. Nat. Hist., vol. 



34, p. 57, pi. 8, fig. 34. 



Description. Shell small, lenticular, broadly ovate, or subcircular in 

 outline, the width usually greater than the length, the greatest width 

 near the mid-length of the shell. The dimensions of the internal cast of a 

 pedicle valve are: length 11.2 mm., width 13 mm., convexity 3.5 mm. 



Ventral valve moderately convex, the greatest convexity posterior to 

 the middle, the surface curving gently from the point of greatest con- 

 vexity to the lateral and anterior margins, and somewhat more abruptly 

 to the cardinal margin; sinus obsolete or rarely very faintly developed 

 near the anterior margin ; the beak pointed, scarcely incurved, projecting 

 beyond that of the opposite valve ; internally a strong median septum is 

 developed which reaches nearly half way from the beak to the anterior 

 margin, and supported by the septum is a well-developed spondylium; 

 near the hinge-line a small, horizontal plate is developed from each side, 

 connecting the outer surface of that structure with the inner surface of 

 the valve, on each side of the median septum on the internal casts, the 

 surface is marked by radiating vascular sinuses which dp not reach the 

 anterior margin of the valve. 



Brachial valve equally or a little less convex than the pedicle, the 

 greatest convexity posterior to the middle, the surface curving gently 



