154 PLEtJRO'fOMIDjE. 



Synopsis of Genera. 



I. Pleurotominae. 

 Genus PLEUROTOMA, Lamarck, 1799. 



Shell turriculated, fusiform ; spire long, sharp ; aperture ovate, 

 the columellar margin smooth, the outer lip with a narrow pro- 

 found sinus separated rather distantly from the suture ; canal 

 long and narrow, straight, open. 



Animal, foot truncated anteriorly, obtuse posteriorly ; tentacles 

 cylindrical, with eyes externally near their base; teeth falciform, 

 angulated (1-0-1). Dentition, PL 33, fig. 54. Generally large 

 shells variegated with spots. Inhabiting warm seas. Fossil, 



tertiary. 



Subgenus GEMMULA, Weinkauff, 1875. 



Shell spindle-like, canal rather long and narrow, sometimes 

 curved ; sinus straight, more or less narrow and long, terminating 

 a nodulous peripheral keel ; embryonal whorls three or four, the 

 two upper ones smooth, upright, the others longitudinally 

 ribbed. 



Consists of a few species having upright embryonal whorls, 

 these being inclined in Pleurotoma. 



Genus GENOTIA, H. and A. Adams, 1853. 



Shell narrowly obconic, cancellated, body-whorl gradually 

 tapering to a but slightly developed canal ; lip-sinus wide and 

 shallow; aperture long and narrow, with subparallel margins. 

 Operculum unguiculate. 



Animal resembling Conus. 



The name is derived from Genot, by which Adanson called 

 the type species. W. Coast of Africa. 



Pseudotoma, Dolichotoma, Oligotoma and Ronaultia of Bel- 

 lardi and Cryptoconus, Koenen, are sections containing European 

 tertiary species. Their characters are not important. 



Genus COLUMBARIUM, E. von Martens, 1881. 



Shell fusiform, carinated, spiny ; embryonic tip of the spire 

 globular ; aperture short, oval ; sinus of the lip scarcely indicated 

 by a slight curve ; canal narrow, very long. W. Australia, China, 

 Panama. The group is placed here by von Martens on account 



