214 PLIOCENE MOLLUSCA. 



prominently carinated, the last being two-tliirds the total length, excavated below ; 

 suture less clearly marked ; canal longer and more distinct ; mouth wider in 

 proportion ; outer lip somewhat expanded. 



Dimensions. — L. 30 mm. B. 14 mm. 



Distribution. — Not known living. 



Fossil : Waltonian Crag : Little Oakley. Newbournian : Wal- 

 dringfield. 



Upper and Middle Oligocene : Denmark. Miocene : Schleswig and Vienna 

 basin. 



Remarks. — In addition to the large and coarsely sculptured fossils described 

 above, a smaller and more delicate form has been found, though rarely, in the English 

 Crag, not unlike that figured by Homes as P. intorta. At first sight the two 

 seem sufficiently distinct to justify our regarding them as separate species, indeed 

 Bellardi, alhiding to Homes' P. intorta, expresses a strong opinion that they are 

 so. These extreme forms, however, appear to be more or less connected by others 

 of an intermediate character, and it may be therefore convenient to group them as 

 varieties of one species. It is Wood's P. Morreni, rather than that of De Koninck, 

 that is to say, the smaller of the two, for which I think the varietal name Morreni 

 should be reserved. 



[Since the above was written I have received some specimens from Dr. Ravn, 

 showing the connection between the two shells. One of these from the Upper 

 Miocene of Denmark, which I have figured (Plate XXVI, fig. 14), corresponds 

 more or less nearly with the Crag form of the typical P. intorta and. with that from 

 the Italian Pliocene which is smaller. On the other hand, the fossils Drs. Ravn 

 and Harder figure {op. cit.), from the Middle Oligocene of Denmark, are what I 

 have called var. Morreni, agreeing with my figures 15 and ] 6 from the Crag and 

 with that given by Homes from the Austrian Miocene. Dr. Ravn considers, as I 

 do, that the two forms are distinct, but that the one is a variety of the other.] 



Genus BORSONIA, Bellardi, 1838. 

 Borsonia suffolciensis (A. Bell, MS.) sp. nov. 



1879. Borsonia prima (A. Bell) S. V. Wood, Mon. Crag Moll., 2nd Sujjpl., p. 21, pi. iii, fig. 1. 



Specific Characters. — Shell strong, fusiform ; whorls slightly convex, depressed 

 above ; spire elongate, turreted, regularly tapering ; suture slight but distinct ; 

 mouth long, narrow, passing without break into the canal; columella with a 

 prominent fold or tooth. 



