78 PLIOCENE MOLLUSCA. 



appearance. Mr. A. Bell lias recently found a perfect specimen of this variety at 

 Cranstal Point in the Isle of Man. Pig. 2, var. cloiujafn, is somewhat similar, but 

 the whorls are more convex, the sculpture coarser, the shell rather rugose, and 

 the spire, as a rule, more elongated. Pig. 4, Ysir. fe nest rata, is a tumid form with 

 reticulate sculpture, the transverse and longitudinal costse being further apart than 

 in the type, and nearly equidistant; moreover it is not so distinctly granulate. 



Out of many hundred specimens in my collection from Oakley, these four 

 varieties named may be more or less easily separated. We may regard them as 

 incipient species, which might eventually have become distinct. 



Nassa graiinlata is not known as a fossil from any horizon older than the 

 English Crag, but Jeffreys gives it, probably in error, as West European.^ AYood 

 states, however {fide A. Bell), that it is living in Japanese seas. 



Buccinam (jrnindafuiii, Philippi, is a different species. 



Nassa Dautzenbergi, sp. nov. Plate V, figs. 5, 6. 



SiJecific Gliaracters. — Shell short, ovato-conical, tliick and strong ; whorls 

 slightly convex, regularly tapering to a blunt point, the last more than half the 

 total length ; ornamented by prominent rounded tubercles of regular form, 

 arranged in longitudinal and transverse rows, extending nearly, but not quite to 

 the base of the shell ; in the type there are eight or nine roW'S of the latter on the 

 body whorl, and four or five on the next above it ; suture fairly deep ; mouth 

 short, oval, with an angulate notch at the upper end, and a tooth on the left of it ; 

 outer lip thickened outside and denticulate within ; inner lip reflected on the 

 pillar ; canal very short. 



Dimensions. — L. lo mm. B. 7 mm. 



Distrihiition. — Not known living. 



Fossil : Waltonian Crag : Walton-on-Naze, Little Oakley (rather 

 rare). Newbournian : Newbonrn (Ogden). Butleyan : Butley. Probably else- 

 Avhere in the Red Crag. 



Remarks. — Out of the many specimens of the smaller Nassas I have examined 

 from Oakley there are some which, separating themselves from N. propinqna on 

 the one hand and N. gramdata on the other, form a distinct group, varying 

 somewhat inter se in size and sculpture, but ahvays maintaining a special character 

 of their own. I adopt for them the above name in honour of the distinguished 

 conchologist whose work is so often referred to in this Monograph. 



In sculpture they approach N. propinqna and differ from N. granulata : in 

 form and size, in the mouth, and especially in the thickened outer lip, on the 

 other hand, they come nearest to the latter. N. granulata is ornamented with 

 distinctly elevated longitudinal ribs, crossed by raised and continuous spiral lines 



1 M. Dollfus informs rae that neither he nor M. Dautzenberg know of any Nassa living in the 

 West European region which approaches, even remotely, the present species. 



