289 Bulletin 5 ^9 



Say on Shells, &c. 41 



Species. 



I B, ovata, elongated ;, trans verse septa subovate, sixlo- 

 bed and a smaller one behind ; 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 

 siphuncle) small not shmous, second lobe with a smgle pro- 

 jection each side and sinus at tip, third lobe dilated, with a 

 small sinus each side and more obtuse and profound one at 

 tip, posterior lobe hardly larger than the lateral intermedi- 

 ate ones. . • r, J 

 Greatest diameter of the transverse section one inch and 

 one fifth, smaller diameter seven tenths ; length of the seg- 

 ment about half an inch. . 



The specimen is in the collection of Mr. Reuben Haines 

 of this city it was found on the Neversink hills, m Mon- 

 mouth County, New-Jersey, it is a cast of three very entire 

 ' segments, no vestige of the shell remaining. The dimen- 

 sions are taken from the largest segment. 



In point of form this species approaches B. vertebralis, 

 Lam. particularly in the curvature of the transverse section, 

 but it is somewhat more obtuse behind ; another difference 

 consists in the form of the lobes, which, in that species as 

 represented by Mr. Desmarest, are less symmetrical, des- 

 titute of the lateral processes and of the profound terminal 

 sinus • that species also is very diminutive. 



2 B, cornpressa, elongated, much compressed ; tra7isverse 

 septa oblong-oval narrowed to each end; lobes dilated, 

 dentated on their edges, each with from three to five si- 

 nuses each side and a very profound one at tip. 



This description is taken from two fragments in the col- 

 lection of the Academy of Natural Sciences, which were 

 brouo-ht from the Missouri, one by Messrs. Lewis and Clark 

 and the other by Mr. Thomas Nuttall. As they exhibit the 

 appearance of having been violently compressed by fortu- 

 itous circumstances, I have not been able to obtain correct 

 proportional dimensions of the species. But notwithstand- 

 ing this distortion of form, I have much confidence m placing 

 it next in specific affinity to B. Knorriana, Desm. as it has 

 without doubt been naturally a much compressed shell, with 

 the lateral edges not very unlike those of that large and re- 

 VOL. II No. I. 6 



