178 BuivIvETlN 31 178 



This shell is larger, thinner, more inequilateral than the preceding 

 [(^guorea], and very rare. The cardinal plate is less thickened and the an- 

 terior muscular impression not so deeply impressed. Both species have an 

 indistinct impressed line on the exterior, extending from the anterior end 

 to the apex. 



This is indeed a rare species but is so much thinner than 

 tsquorea and with so much wider hinge area that a comparatively 

 fragmentary specimen can be quickly differentiated from speci- 

 mens of the latter species. Our specimens were from the famous 

 Claiborne "sand bed". 



Pteropsis papyria Conrad, PI. 54, Fig. 13. a 



Lutraria papyria Con., Foss. Sh. Tert. Form., 1833, p. 41 ; pi. 19, fig. 



7, Harris' Reprint. 

 Madra dentata Lea, Cont. to Geol., 1833, p. 41, pi. i, fig. 9. 

 L. papyria Con., Amer. Jour. Sci., vol. i, 1846, p. 216, pi. i, fig. 8. 

 Pteropsis papyria Gabb, Jour. Phila. A. N. S., vol. 4, i860, p. 296. 

 Pteropsis papyria Dall, Trans. Wag., Ill, 1895, p. 881. 



Conrad'' s best characterization (Amer. Jour. Sci.). — Ovate, very thin 

 and fragile, inflated anteriorly ; surface with concentric sulci, profound on 

 the sides and obsolete in the middle, and with numerous interrupted wrin- 

 kled lines from umbo to base ; anterior end abruptly rounded ; posterior 

 side cuneiform, compressed, gaping ; a slight fold, and nearer the end 

 margin, an undulated line from beak to base ; submargin angular, with a 

 narrow depressed area at the extremity of the valves. Claiborne, Alabama. 



A very rare species and exceedingly fragile. I have only one valve 

 nearly perfect and the fragment of another. The teeth and cardinal 

 grooves are remarkably large and profound. 



Small fragments of shells belonging to this species are not so 

 very rare in the Claiborne sand bed, but we have succeeded in 

 finding no really good specimens that would stand packing and 

 shipment. So far as we are aware it is found only in the sand 

 at Claiborne, Ala. 



There are now two nearly perfect left valves in the Conrad- 

 ian collection at the Phila. Academy. 



Pteropsis lapidosa Conrad, , PI. 54, Figs. 14-15 



Lutraria lapidosa Con., Amer. Jour. Sci., vol, i, 1846, p. 215, pi, i, 

 fig- 7- 



