Casey — Notes on the Pleurotomidae. 143 



erable number by Mr. T. H. Aldrich, to whose generosity I 

 owe the examples before me. 



Cochlespiropsis n. gen. 



This genus is allied to Cochlespira but differs greatly in 

 having the beak obliquely elevated near the tip, the periphery 

 of the whorls simply angulate in profile and not lamellarly 

 expanded, reflexed or crenulate and the sculpture extremely 

 minute and feeble, close-set and even, wholly differing in 

 character from that prevailing in OocJdespira. The genus 

 seems to have become extinct by the middle of the Eocene, 

 not occurring above the Lower Claiborne, and, in fact, limited 

 as far as known to that epoch. The two cpecies before me 

 may be distinguished as follows : — 



Spire above the periphery of the body whorl evenly and rather rapidly 

 acuminate, shorter than the portion below that periphery; sculpture of 

 the body whorl below the periphery consisting of moderately close- 

 set and distinct spiral threads which are somewhat uneven in size. 

 Length of a specimen of 7 body whorls, 20 mm.; width, 6.5 mm. 

 Lower Claiborne Eocene of Wheelock, Texas eugonata Con. 



Spire above the periphery more elongate, nearly equaling in length the 

 portion below, very gradually acuminate and more rapidly and 

 arcuately so toward apes; ornamentation of the body whorl below the 

 periphery consisting of extremely minute, closely crowded and equal 

 spiral threads which are frequently somewhat wavy or subinterrupted 

 by uneven irregularities of growth. Length of a specimen of 8 body 

 whorls, 31 mm.; width, 8.8 mm. Lower Claiborne Eocene of Lisbon, 

 Ala blanda n. sp. 



There is no vestige of a tumid or carinulate collar below 

 the suture in this genus. 



Cochlespira Con. 



The periphery is lamelliform to a greater or less degree in 

 this genus, the edge always crenulate and bent backward, and 

 there is usually a well-marked and finely beaded collar below 

 the suture which, however, sometimes becomes obsolete on 

 the larger whorls. The posterior broad fasciolar surface has 

 some fine spirals near the periphery but is usually completely 

 devoid of sculpture elsewhere, except the arcuate lines of 



