170 PLIOCENE MOLLUSCA. 



finer ones in the interspaces which are inconspicnonson the npper whorls but more 

 prominent on the last ; spire rather long, ending in a blunt, submammiform apex ; 

 suture deep ; mouth oval ; outer lip thin, somewhat expanded ; inner lip forming a 

 thin glaze, adherent to the pillar ; canal short, wide and open. 



Dimensions. — (Of Crag shell.) L. 60 mm. B. 80 mm. 



Distribution. — Butlejan Crag : Butley. Icenian : Thorpe near Norwich. Un- 

 known from older horizons of the Crag. 



RemarJes. — The Butley fossils ^ere figured are from the Sedgwick Museiun at 

 Cambridge, and there is a similar specimen from the Icenian Crag of Thorpe in the 

 Fitch collection at the Norwich Museum. In form they agi-ee with the antiqiia 

 group though the sculpture is different from any variety of that species known to me; 

 they seem full-grown, belonging perhaps to some smaller shell like that figured by 

 Prof. Leche as N. tomato^ which is not unlike our own except that the spiral ril^s of 

 the latter are more numerous ; they differ too widely, however, from the type of 

 that species to be identified satisfactorily with it. I describe them therefore provi- 

 sionally as a variety of N. antlqna ; they seem to be one of the intermediate forms 

 which connect it with N. despeda. None of ray Scandinavian correspondents know 

 this form from polar seas. It differs from the strongly ribbed varieties of the 

 latter before described in the absence of a distinct keel. 



Var. icenica, nov. Plate XIX, fig. 11. 



Dimensions. — L. 55 mm. B. 27 mm. 



Distribution. — -Fossil : Icenian Crag : Dunwich, Easton Bavent. 



Bemarls. — This Yerj graceful variety, which differs from the type in its slender 

 form and narrow aperture, is unknown to me from any other than the Icenian zone. 

 The shell here represented is from my own collection. It may possibly be related 

 to Jeffreys' unfigured variety gracilis (Brit. Conch., vol. iv, p. 325), but I have 

 not seen his specimen. Mr. Robson informs me, however, that there is nothing- 

 like it in the British Museum. 



Summarising the facts given above it appears that the various forms of 

 Neptunea found in the East Anglian Pliocene have a zonal value, although this has 

 been generally overlooked. The oldest part of the Red Crag, that of Walton-on- 

 Naze, contains practically nothing but the different varieties of the sinistral 

 species N. contraria. Dextral shells, widely different from the latter, appear at 

 Little Oakley in what I regard as an upper part of the AValtonian, but they are 

 vastly outnumbered by the former, becoming somewhat more abundant in the later 

 beds of the Red Crag; it is N. despecta and its varieties, however, that are the 



1 K. Sveask. Vet. Akad. Haudl. Stockholm (n.s.),vo1. xvi [2], p. 67, pi. ii, fig. 28 rt, 28 6, 1878. 



