5S BurxKTiN 31 58 



but dipping down and passing out at both anterior and posterior 

 margins. Of these heavier pseudo-concentric ridges there are a 

 dozen or fifteen larger ones on the upper and medial portion of 

 the shell. But as they extend over the basal portions the}- be- 

 come much finer. There are, as Conrad says, "three minutel}' 

 crenulated, carinated lines diverging from the apex" with hints 

 at short intermediate ones. Radiating from the umbo to the an- 

 terio-basal margin there is a slight depression, and it is as the 

 pseudo-concentric lines cross this slight depression that the}' dip 

 down and extend out laterall}' across the concentric structure. 

 The teeth are V-shaped and strong, and it is doubtful whether 

 the valves could be disunited without fracturing the teeth. 



We know this species only from the Claiborne sand bed at 

 Claiborne, Ala. 



The specimens figured are from this localit}' and are in the 

 Paleontological Museum at Cornell. 



Leda ccelatoides n. sp., PI. 23. Fig. 10. 



Specific characterization. — For general outline and ornamen- 

 tation, see pi. 23, fig. 10. Pseudo-concentric lines far more num- 

 erous on the face of the shell than in coelata, and lacking entirely 

 the downward dip as they approach the umbonal ridge. Shell 

 less protracted than ccelata. It may be considered as about mid- 

 way between ro'/fl'/a and mzdtilineata Conrad. 



Type and specimen figured. — Paleont. Mus. Cornell Univ. 



Locality and horizon . — Wautubbee, Miss., St. Maurice stage. 



Leda multilineata Conrad, PI. 23. figs. 11, 12. 



L. viultilhteata Q.on., Proc. Acad. Nat. Sci. Phila., 1855, p. 258. PI. 14, 



fig. 4 of Wailes' Agr. and Geol. of Miss., 1854. 

 L. multilineata Dall, Trans. Wag. &c., Ill, '98, p. 588, pi. 25, figs. 11, 



II, a. 



Conrad's original description. — Ovate-elliptical, inequilateral ventri- 

 cose, with fine, sharp concentric lines which are somewhat undulated : an- 

 terior side rostrated, with closely arranged, radiating minute, tuberculated 

 striae ; posterior side with unequal, fine radiating lines, a few of which are 

 very distinct ; a few radiating lines are continuous near the base over the 

 middle of the valves. Allied to N'. coelata but very distinct. 



