456 Systematic Paleontology 



Collections. — Maryland Geological Survey, Columbia University. 

 Outside Distribution.- — Monmouth Formation. Navesink marl, New 

 Jersey. 



Genus PYRIFUSUS Conrad 

 [Jour. Acad. Nat. Sci., Phila., 2d ser., vol. iii, 1S58, p. 332] 



Type. — Pyrifusus subdensatus Conrad. 



" Pyriform, columella broad, thick, flattened ; body volution transversely 

 oval."— Conrad, 1858. 



In 1876 Meek united under Pyrifusus the typical species of Conrad and 

 a group of forms differing from P. subdensatus in the higher, more evenly 

 inflated spire, the sinuous outer lip and the flattened columella. The 

 latter he assigned to the subgenus Neptunclla, a name unfortunately pre- 

 occupied by Gray in 1853. 



It seems probable, however, that the differences are of more than sub- 

 generic significance, but Pyrifusus sensu stricto is not represented in the 

 Maryland faunas, and so it seems wiser to leave the status of the group 

 unchanged until further material is available. Rhombopsis, a name sug- 

 gested by the conspicuously rhomboidal outline of the shell, may be sub- 

 stituted for the preoccupied Neptunella. The composite genus is described 

 by Meek as follows : 



" Shell varying from subpyriform to short-fusiform ; spire one to three- 

 fifths the length of the aperture and canal, not papillate at the apex ; body 

 volution rather ventricose and prominent, or obtusely subangular around 

 the upper third, dorso-ventrally compressed, or more generally rounded, 

 tapering below into a nearly straight, moderately produced canal ; aperture 

 rhombic-subovate in outline, being angular, but not notched or canalicu- 

 late above, and tapering downward ; outer lip thin, sometimes broadly 

 sinuous above the middle; columella solid, gently arcuate along the 

 middle, nearly straight, and without twist below, sometimes more or less 

 flattened, but always without the slightest umbilical ridge, and at least 



Etymology: A name which combines the roots as well as the characters 

 of Pyrula and Fusus. 





