GASTEROPODA OF THE LOWER GREEN MARLS. 65 



FASCIOLARIID^. 



ODONTOFUSUS, new genus. 



Shell univalve, fusiform, resembling Fusus or Fasciolaria in general 

 appearance; spire elevated, with vertically plicated whorls; anterior extrem- 

 ity prolonged into a straight canal of greater or less extent; columella 

 marked near or above the middle by a single oblique fold; surface probably 

 lirated, although no evidence of such a feature remains on the casts. 

 Types 0. (Fasciolaria) Slacki Gabb and 0. typicus Whitf 



I am compelled to propose a new generic name for a group of species 

 possessing the above characters, although reluctant to do so on internal 

 casts. The specimens closely resemble specimens of Fusus or Fasciolaria 

 in their elongated fusiform character and prominent volutions, which have 

 been strongly marked by vertical folds; but they differ from either in the 

 characters of the columellar ridge or fold. From Fusus they differ in its 

 presence and in the straight beak, and from the other in having only a 

 single ridge, which is placed much higher on the columella. Mr. Gabb 

 noticed the ridge on the columella in his original description of F. Slacki. 

 and in some later remarks^ he suggests its relation to Piestochilus Meek. 

 Mr. Meek's genus usually possesses more than one fold, but differs very 

 materially in the characters of the spire and the more elongated anterior 

 beak. In fact, Piestochilus more closely resembles Mitra than Fasciolaria. 

 The shells referred to Borsonia and Cordieria also "somewhat resemble 

 these, but possess a distinct sinus in the lip like Pleurotoma and are shorter 

 in front as well as having denticulations on the inside of the outer lip, 

 features which these shells have not possessed. It is somewhat uncertain 

 whether there have been spiral striae on the shell, no evidence of such 

 feature being present on any of the many casts examined. In general 

 features the genus resembles somewhat Cordiera A. Rouault, but there is no 

 evidence of a sinus or slit in the lip allying it to Pleurotoma, as in that one. 

 Cordiera is from the Eocene in Europe. 



' Proc. Acad. Nat. Soi., Phila., 1876, p. 282, 

 MON XVIII — —5 



