OLIGOTOMA PANNUS. 215 



Dimensions. — L. 40 mm. B. 15 mm. 



Distribution. — Not known living. 



Fossil : Newbournian : Walclringfield (derivative) . 



Bemarlcs. — The genus Borsonia was proposed by Bellardi for a group of shells 

 allied to Psendotoma with a slight sinus and a prominent fold or tooth on the 

 columella. The fossil described by Mr. A. Bell as Borsonia prima is one of the 

 large Pleurotomas characteristic of the older Pliocene, and but sparsely represented 

 in the East Anglian Crag. It was found by him at Waldringfield, where it was no 

 doubt derivative from some older deposit of the Anglo-Belgian basin. As the 

 name had been previously used by Bellardi for a different species, Mr. Bell proposes 

 to alter it as above. He still thinks it may be referred to Borsonia, although 

 "Wood was somewhat doubtful about it. 



Genus OLIGOTOMA, Bellardi, 1875. 



Olig-otoma pannus (Basterot). Plate XXVII, figs. 8 — 11. 



1825. Pleurotoma 2Mnnus, Basterot, Descript. Coq. foss. Bordeaux, p. 63, uo. 2. 



1832. Pleurotoma pannus, Grateloup, Tab. Coq. Dax, p. 331, no. 346. 



1847. Pleurotoma jmnnus, Bellardi, Mem. K. Accad. Sci. Torino [2], vol. ix, p. 555, uo. 10, pi. ii, tig. 1. 



1877. Oligotoma panmis, Bellardi, Moll. Terr. Terz. Piem., pt. ii, p. 236, pi. vii, fig. 23. 



1886. Genotia (Oligotoma) pannus, Dollfus et Daiitzenberg, Et. prel. Coq. foss. Touiaine, p. 9. 



1890. Oligotoma pannus, Sacco, Boll. Soc. Geol. Ital., vol. ix, p. 279, no. 4235. 



Specific Characters. — Shell subfusiform, elongato-subulate, not carinated; whorls 

 flat or nearly so, the last more than half the total length ; ornamented by well- 

 marked spiral ridges, intersected by rather oblique longitudinah costas, not very 

 prominent, and by the lines of growth, giving the shell a sub-reticulate appearance ; 

 sutiire slight ; apex rather blunt ; mouth oval, narrow, angulate above ; columella 

 with a distinct fold, excavated above ; canal short. 



Dimensions. — L. 14 — 18 mm. B. 6 mm. 



Distribution. — Not known living. 



Fossil : Waltonian Crag : Little Oakley. Miocene : France — 

 Touraine, Bordeaux; Italy (Tortoniano, Elveziano). 



Bemarks. — The generic name Oligotoma was proposed by Bellardi for a group 

 of the Pleurotomidse, 0. Basterot! , Desm., being taken as the type; they have 

 an acutely elongate spire transversely ridged and cancellated, a short canal, a wide 

 but shallow sinus placed at some distance from the suture and a contorted 

 columella with a distinct fold upon it. He remarks that it may be separated 

 without difiiculty from other genera of this family. 



