91 St. Maurice and Ci^aiborne Pelecypoda 91 



Conrad'' s original description. — Shell oval with concentric sulci ; 

 posterior side with a slight groove or fold terminating in a slight emargin- 

 ation of the basal edge ; umbo flattened ; apex acute but not prominent ; 

 muscular impressions a little elevated and very distinct. Length half an 

 inch. 



Locality. — Claiborne, Ala. London clay. 



Conrad must have had an immature specimen in hand when 

 he was describing this shell as its usual adult length is not Ya 

 but ^ in. De Gregorio figures some young, fiat shells as a var- 

 iety ebla but admits that the variety is not very well defined. I^ea 

 based his sulcata on a shell he described as practically nicklinii, 

 minus the peripheral crenulation. 



This species shows a remarkablj^ wide range of variation, 

 from somewhat elongate with deep radiating channel to nearly 

 circular with practically no channel. However, the postero- 

 basal margin is always somewhat truncated and the beaks central 

 in comparison with smithvillensis from Texas. The general 

 character of surface undulations is quite different in the two 

 species. 



Type. — Conrad collection, Phila. Acad. 

 Horizon. — Claiborne Eocene. 

 Specimens figured. — Paleont. Mus. Cornell Univ. 

 Locality. — Claiborne, Ala. 



Astarte triangulatoides, n. sp., PI. 32. Fig. 12, a. 



Specific characteriztion. — Form and size as indicated by the 

 figures and explanation ; more broadly ovate and less triangular 

 than triangulata Mr. ; no flattening of the umbones as in the var- 

 ietal forms of smithvillensis ; exterior with regular, symmetrical- 

 ly arranged concentric lines or lirations ; margin crenulated with- 

 in as shown on a second specimen (not the worn type) . 



This is evidently of the triangulata stock but besides the 

 differences between these two species as noted above this is with- 

 out the excessive lunule excavation of triangulata and is only 

 one-half as large. It is double the size oi A. aldrichianalciax., 

 with less rounded base. 



