47 



Sub-family Ptychatfactvriee* Differs from Fa^ciolariinse in lingual 



dentition, and includes only three small boreal species. 

 Sub-family Peristerrfiinse, Columella with transverse plications. 



Synopsis of Genera. 



Sub-Family FUSING. 



FUSUS, Lam. Shell fusiform or spindle-shaped ; spire many-whorled, 



acuminate, longer than the last whorl ; aperture oval ; canal long, 



straight, narrow ; columell a smooth, arcuated. Dentition, PI. 25, fig. 1. 



Subgenus SINISTRALIA, H. and A. Ad. Shell reversed, fusiform ; canal 



long ; whorls rounded. 



AFEE, Conrad. Shell short fusiform, spire and canal moderate, body 

 whorl rather large, shouldered and tuberculate, aperture channelled 

 behind, outer lip dentate within. (Professor Meek * states that the 

 fossil species described by Conrad, are not congeneric with the type, 

 the recent Fusus afer, Lam,, and he refers them to Conrad's genus 

 Pyrifusus, one of the forms of N<ptuniince.) 



CLAVELLA, Swains. Shell solid, thick, subfusiform ; spire acuminate; 



last whorl suddenly contracted in front, thickened and rounded next the 



suture ; aperture narrow, canal long and straight ; columella excavated 



in the middle ; outer lip simple. Operculum ovate ; nucleus apical. 



Dentition, unknown. 



Peistocheilus, Meek. Described as a subgenus of Fasciolaria, appears to 

 be identical with Clavella, as Meek himself subsequently suspected. 

 The columellar plaits are nearly obsolete, situated so far within the 

 aperture as to be barely visible and in many specimens are not seen 

 at all. Clavella itself occasionally shows these adventitious and in- 

 conspicuous plaits. The shell is so decidedly fusiform that I place it 

 in the Fusinae in preference to the Fasciolariinse despite these folds. 

 The dentition of Clavella distorta corresponds with that of Cantharus, 

 Euthria, etc., with which the genus has heretofore been associated in 

 the sub-family Pisaniinae, and this species and its allies are also con- 

 chologically related to that sub-family, but the fossil types and the 

 recent C, serotina are generically different, so that the genus as thus 

 restricted must be placed here. 



I figure the type of Meek's subgenus Peistochilus. 



P. Scarboroughi, Meek and Hayden, PI. 28, figs. 41, 42. Cretaceous ; 

 Butte au Ores, Missouri River. 



BUCCINOFUSUS, Conrad. Shell ventricose, spirally sculptured ; epi- 

 dermis pilose ; spire produced ; canal moderate in length ; columella 



Pal, Hayden's Survey., IX, 344. 



