GASTEROPODA. 43 
Length, #ths of an inch. 
Locality. Coralline Crag, near Orford. 
The specimen figured was found by myself, and Mr. Bell has very recently obtained 
several more from the same place. There is a considerable difference among the 
specimens, some being more elongated than others; the shorter are strongly ribbed 
on the body whorl, while on the longer the ribs become nearly obsolete. On the last 
volution the whorls are very slightly shouldered, and the sinus is broad and shallow. 
Clavatula concinnata, ‘Crag. Moll.,’ vol. i, p. 61, Tab. VII, fig. 11, a, 6, are probably 
varieties of this species. ‘This is quite distinct from P/. decussata, Lam., as also from 
Pl. decussata of Couthouy. Rhaphitoma plicatella, Jan., is closely allied, but seems to 
have fewer ribs. 
PLevRotoMA PYRAMIDALIs, Sfrém. Supplement, Tab. III, fig. 9, a, 4, Tab. VII, fig. 22. 
Localities. Red Crag, Butley. Fluvio-marine Crag, Thorpe, m Suffolk (Bel/). 
Upper Glacial, Bridlington. Post-glacial, March and Kelsea Hill. 
The specimen of this well-known northern shell represented in fig. 9 of Tab. ITT is 
one found by Mr. Bell in the Red Crag of Butley ; and that m the fig. 22 of Tab. VII 
is one of a suite from March found by Mr. Harmer. They differ slightly, but may both, 
I think, be referred to this species. The Crag shell has the body whorl smooth, but 
there are indications of longitudinal riblets on the upper volutions. I cannot see any 
spiral stria, but these may be obliterated by attrition. Some of the March specimens are 
perfectly smooth without appearing to have undergone much wear, but in others faint 
traces of riblets on the lower whorl are apparent. A specimen from Bridlington is in the 
British Museum, and it is given from Kelsea Hill by Mr. Jeffreys. The species is given 
from Thorpe in Suffolk by Mr. Bell in ‘Ann. and Mag. of Nat. Hist.’ for September, 1870. 
PLEUROTOMA BICARINATA? Couth. Supplement, Tab. VI, fig. 17. 
Locality. Red Crag, Butley. 
The specimen figured was found by myself at Butley. It very much resembles 
P. violacea of Meig. and Ad., but seems still closer to bicarinata, Couth., as there are 
two very distinct carinee on the whorls. 
Many of the forms of Plewrotome, both those in the Crag and those living in British 
and Northern seas, run so much into each other, and are, withal, so inconstant in their 
characters, even among a group of individuals of apparently the same species, that I feel 
the greatest difficulty in assigning specific names, and I have therefore placed a note of 
interrogation against the name of this species. 
