HYDE: CAMAROPHORELLA. 57 
Camarophorella lenticularis (White antl Whitfield). 
1862. Pentamerus lenticularis White and Whitfield, Proc. Boston soc. 
nat. hist., vol. 8, p. 295. "Chemung group," Burhngton, Iowa. 
1865. Pentamerus lenticularis Winchell, Proc. acad. nat. sci. Phila., p. 117. 
Yellow sandstone and base of Burlington limestone, Burlington, Iowa. 
1894. Camarophorella lenticularis Hall and Clarke, Thirteenth ann. rept. 
state geol. [of New York], pi. 45, figs. 5, 6. Yellow sandstone of the Burling- 
ton group, Burlington, Iowa. 
1895. Camarophorella lenticularis Hall and Clarke, Geol. surv. New York, 
palaeontology, vol. 8, pt. 2, pi. 62, fig. 46-48. Yellow sandstone of the 
Burlington group, Burlington, Iowa. 
1901. Camarophorella lenticularis Weller, Trans, acad. sci. St. Louis, vol. 
11, no. 9, p. 162, pi. 14, fig. 11-13. Kinderhook, Burlington, Iowa. 
"Shell small, broadly ovate, or subcircular; length and breadth 
nearly equal, profile lentiform. Valves subequal, depressed convex. 
Beaks small, pointed, slightly incurved, sides and front regularly 
rounded. Ventral valve a little the most convex; the beak pointed, 
and projecting beyond that of the dorsal. Spoon-shaped process of 
the interior of the ventral valve proportionally large, in some speci- 
mens nearly one-third the width of the shell, and extending about one- 
third the length of the valve; longitudinal septum reaching to near 
the center of the shell. Interior of dorsal valve with a single longi- 
tudinal septum, with horizontal plates curving toward the cavity of 
the opposite valve. Strong radiating muscular or vascular markings 
appear on internal casts of both valves. 
"Surface apparently smooth, without mesial fold or sinus. 
"This species has the general form of P. ohlongus as it occurs in the 
Clinton group of New York, but is quite small, seldom measuring 
more than six-tenths of an inch in length. The internal characters 
of the ventral valve are precisely those of Pentamerus, but those of 
the dorsal valve vary somewhat from those of most species of the 
genus, in having but one longitudinal septum, with the crural append- 
ages spreading horizontally from it." 
The writer has been able to compare the t\^e specimens of C. lentie- 
idaris with the Sciotoville species. The former is the smaller of the 
two as will be seen by comparing the following measurements of the 
internal molds with those of C. mutabilis: 
Height. 
Breadth. 
14.3 mm. 
16.0 mm, 
12.3 
11.7 
9.5 
10.5 
