2 
42 CRETACEOUS GROUP 
given different names to the same species; but as his has 
priority, I of course abandon mine. 
2. S. reniformis, (S. G. M.) pl. ii. fig. 6. 
Specific character. Ventricose in the middle, tapering ra- 
pidly towards each end; with numerous coste that bifurcate 
laterally. 
Less than inch in length. 
A solitary and imperfect cast was found by Mr. Conrad 
in the friable marl at Grove mill, near Bordentown, N. J. 
Allied to S. striatus of the British chalk. 
Bacutires. Faujas. 
1. B. ovatus, (Say,) pl. i. fig. 6, 7, 8. 
Journ. Acad. Nat. Sciences, vol. vi. pl. v. fig. 5,6. Amer. 
Journ. of Science, vol. xviii. pl. i. fig. 6, 7, 8. 
Specific character. Transversely suboval, with semi-ellip- 
tical lateral undulations ; septa six-lobed, and a smaller one be- 
hind; lobes of the superior faces of the septa three on each 
side, with a minute one between each, dentated at their edges: 
anterior lobe, (nearest the siphunculus,) small, not sinuous ; 
second lobe with a single projection at each side, and sinus at 
the tip; third lobe dilated, with a small sinus at each side, and 
a more profuse and profound one at tip; posterior lobe scarcely 
larger than the lateral intermediate ones. 
The above description is derived from Mr. Say, ex-. 
cepting the undulatory sides, which is obvious in all the 
more perfect specimens I have seen, as in fig. vi. of pl. 1. 
In other instances, (PI. i. fig. viii.) these undulations are 
scarcely perceptible, owing probably to attrition. Such 
is the case with the original specimen described by Mr. 

