NOTICE OF PALEONTOLOGY OF NEW YORK. 



183 



The internal spires of this species, in their first volution and in the 

 accessary lamellse, are quite distinct from those of A. spiriferoides. The 

 accompanying figure is an illustration of the first volution of its spires, 

 with the accessary lamellae. 



The bases of the crura are shown at a, and these projecting a short 

 distance forward make a somewhat abrupt retral curve, turning back in 

 the direction indicated by the dotted lines h; and thence descending 

 into the cavity of the dorsal 

 valve, follow essentially the cur- 

 vature of its outline, as indicated 

 at c, to a point anterior to the 

 middle of the length of the spiral 

 curve. Here the branches of 

 the loop are given ofi" at d; and 

 these projecting vertically into 

 the cavity, are turned abruptly 

 forward, and beyond the dotted 

 line, form a solid pointed plate 

 which projects far towards the anterior limits of the spires at e. The 

 posterior portions are produced backwards, and gradually ascending, con- 

 tinue parallel and in close proximity as far as /, where they diverge, 

 sending off a fillet on each side which at g assumes the curvature of the 

 normal lamellae of the spire, following the same course into the cavity 

 of the valve, and extending forward to the origin of the process forming 

 the loop, they are united to the proper spiral lamellae at h, which then 

 continue simple as shown in their extension to i. 



A second species in the Hamilton group is the Athyris cor a. In the 

 Chemimg group we have the Athyris angelica and the A.? polita. 



GENUS MERISTELLA (Hall). 



The Genus Meristella, separated from Athyris on account of its different 

 external characters and muscular impressions, is represented as follows : 



Meristella nasuta, in the Schoharie grit and Corniferous limestoDe ; 

 in the Corniferous limestone. 



in the Hamilton group ; 



M. 



scitula, ) 



M. 



doris, \ 



M. 



barrisi, J 



M. 



haskinsi, \ 



M. 



rostrata, ) 



M 



meta (n. s.). 



