130 BUI^LETIN 31 130 



Horizo7i. — Sabine-Claiborne inclusive. 



Specimens figured. — Paleont. Mus. Cornell Univ. ; Clai- 

 borne, Ala. 



Localities. — Sabine : Woods Bluff. 



St. Maurice : Winnfield Marble Quarry, La. 

 Claiborne : Claiborne, Ala. 



Diplodonta corbiscula, n. sp., PI. 40. Figs. 20, 21, a 



Specific characterization. — Form and size as indicated by the 

 figure and explanation ; anterior nearly 50 per cent longer than 

 posterior ; cardinal margin strongly developed with a very strong 

 bifid anterior cardinal tooth and a small posterior one ; ligamental 

 channel short, curving from beak to inner margin of shell not 

 far behind the small posterior cardinal ; muscular impressions 

 rather large and ill-defined ; interior rudely radiately striate ; ex- 

 terior smooth, save very fine concentric lining ; lunule wanting. 



The cutting away of the shell margin just anterior to the 

 heavy bifid tooth in the left valve (the only one known) would 

 seem to indicate that there was a ver}^ strong anterior cardinal in 

 the right valve ; doubtless the bifid posterior was strongly de- 

 veloped as the pit is wide and deep in the left valve. Though 

 the shell is thick about the cardinal margin it is thin basally. 



The margin of the valve tends to make lateral teeth. First, 

 as seen just before the bifid cardinal, a narrow fold on the mar- 

 gin winds out from under the beak and as it passes up over the 

 middle of the edge of the shell it is rather prominent and lateral- 

 tooth-like. Second, the margin of the shell just posterior to the 

 basal end of the ligament channel is somewhat tooth-like. 



Type, etc. — Paleont. Mus. Cornell Univ., from Claiborne 

 Eocene, Claiborne, Ala. 



Chama monroensis, PI. 41. Figs, i, ?2-4. 



C. nionroensis Aid., The Nautilus, vol. 26, Jan. 1903, p. 100, pi. 4, 



fig. 15. 



Aldrich's original descriptioji. — Shell of medium size, strongly ru- 

 gosely plicated, lamellar. Upper valve with 6-8 leaves turned up to nearly 



