1 68 Bulletin 31 168 



a little prominent ; lateral teeth large and prominent, compressed ; area 

 above the anterior lateral tooth dilated. 



Of this species I have only an imperfect right valve. Its most re- 

 markable character is the somewhat angulated form of the anterior dorsal 

 margin. Claiborne, Ala. 



Though Conrard refers to a pi. 5, fig. i in his original diagnos- 

 is, it seems never to have been printed. Still, as Dall says, the spe- 

 cies is easily determinable. It occurs in considerable abundance 

 in the St. Maurice Eocene at the base of the Upper Bluff at Clai- 

 borne, but varies extensively in outline from nearly circular with 

 but a slight flexion of the posterior to more elongately elliptical 

 forms assuming an astonishing similarity in outline to Semele 

 linosa. In the higher, older specimens the angle on the anterior 

 dorsal margin, followed below by an oblique truncation seem to 

 be quite characteristic. Some specimens show considerable peri- 

 pheral areas of well marked concentric lines, though the umbon- 

 al regions (as is also the case with linosa) are nearly smooth. 



In examining the types at the Philadelphia Academy it ap- 

 pears that although there is sometimes an outward resemblance 

 between T. raveneli and 6". linosa, the former has stronger lat- 

 eral teeth but a less extended pallial sinus. 



There are now three specimens in the Conradian collection. 

 The single one labelled Tellina {Arcopagia) alta seems to be 

 Conrad's type of rfatz'^w^/z. The two specimens in still another 

 tray labelled T. alta are probably the types of that species. They 

 are more striate, less plicate and show a very deep pallial sinus. 

 However, since raveneli shows such wide variations it is quite 

 possible that alta should be included as a mere variety. These 

 forms seem to be derived from trumajii. 



Type.— Fhila. Acad. Nat. Sci. 



Horizon. — St. Maurice Eocene. 



Specimens figured. — Base of Claiborne Bluff, Ala. ; in Pal- 

 eont. Museum, C. U. 



Localities. — Base of Claiborne Bluff, Lisbon, Ala. ; Orange- 

 burg District, S. C. 



