io8 BuivivKTiN 31 108 



elevated, nearly smootti, the larval shell small, distinct ; hinge armature 

 feeble ; the left posterior lamina small, feeble, short; anteriorly the "hooks" 

 of the two anterior laminse distinct, simulating cardinals, the lateral portions 

 nearly obsolete ; the grooving of the exterior faintly visible interiorly to- 

 wards the anterior end but not crenulating the basal margin ; muscular im- 

 pressions narrow, feeble ; basal margin entire. Long. 3.75, alt. 3.0, diam. 

 1.5 mm. 



A single left valve of this very distinct species was obtained. From 

 B. prima Aldrich, it differs by being grooved, not plicated, in the absence 

 of the punctation which covers the surface in B. prima, and in the much 

 more profuse and finer sculpture. 



Eocene of the Claiborne sands, Claiborne, Alabama ; Burns. 



Bornia plectopygia Dall, PI. 37. Fig. 11. 



B. plectopygia Dall, Trans. Wag., Ill, 1900, p. 1149, pi. 49, fig. 9. 



DalVs original description. — Shell small, short, rounded ovate, pol- 

 ished, smooth to the eye, except for incremental lines and about three faint 

 radial plications on the posterior basal half ; beaks low, distinct ; hinge 

 armature feeble, the distal ', laminse obsolete, the hooks of the left anterior 

 laminae perceptible but not prominent ; anterior side short, rounded, pos- 

 terior side produced downward and backward, the margin indented by the 

 radial furrows, elsewhere entire ; scars obscure. L,ong. 4.5, alt. 4,0, diam. 

 2.0 mm. 



A single left valve of this species was collected which though somewhat 

 imperfect cannot be confounded with either of the other species from this 

 horizon. There is a faint microscopic radial striation on the surface, a sul- 

 cus for the ligament, and a faint excavation for the resilium. 

 Eocene of the Claiborne sands, Ala. ; Burns. 



Bornia dalli Cossman, PI. 37, Fig. 12, a. 



Montacuta dalli Cossm., Notes Compl., 1893, p. 12, pi. i, figs. 13-14. 

 Bornia dalli Dall, Trans. Wag., Ill, 1900, p. 1149. 



Cossm.ann's original description .—Testa, minuta subtrigona, valde 

 inaequilateralis, antice duplo longior, postice truncata et subangulosa, mar- 

 gine palliali rectilineari, umbone, parvo, hand prominulo ; super- 

 fices externa striis fibrosis incrementi ornata, postice angulo decurrente no- 

 tata, in medio plana, antice obliquiter angulata ; cardine bidentato, fossula 

 mediana profunde emarginata ; cicatriculis bene impressis, anterior! longe 

 ac anguste producta. 



