GASTEROPODA. 15 
Nassa reticosa, J. Sowerby. Crag Moll., vol. i, p. 33, Tab. III, fig. 10 ; Supplement, 
Tab. IV, fig. 3, and Tab. VII, fig. 15. 
Localities. Red Crag passim; Chillesford bed, Haston Bavent (Bell). 
This, as before shown, is a very variable shell, and I have here introduced two more 
forms which I think may be referred to the same species. Fig. 3, Tab. IV, of the present 
Supplement represents a small specimen obtained by Mr. Bell from the Red Crag of 
Butley, which has a perfectly cancellated exterior without any thickened ribs or varices, 
which might be called var. semplex, and fig. 15, Tab. VII, is a shell I found in the 
Red Crag of Sutton which has an angulated shoulder to the volution, and belongs, I believe, 
to this species, and I will call it var. sca/arina. 
My. Bell informs me that he has obtained JV. reticosa from the Chillesford bed of 
Easton Bavent Cliff, but I have not seen the specimen. Some fragments of spires from 
the Middle Glacial sand of Billockby seem to belong to the costata variety of this shell, 
but they are too doubtful to justify an identification. 
Nassa coneLopata, Broc. (‘ Crag. Moll.,’ vol. i, p. 82, Tab. III, fig. 9), is possibly 
Buccinum (Desmoulea) abbreviatum, Chemn., a shell living on the coast of Senegal, but 
the shell is so rare in the Crag that I am not certain the fossil and recent shells are 
absolutely identical. 
Nassa Monensis, Forbes, and N. Prtocrna, Strickland, are still uncertain species. 
These two shells, originally described by Strickland, are not to be found. Mr. Etheridge, 
of the Geol. Survey, kindly endeavoured with much trouble to find them, but without 
success. My own shell (Tab. ILI, fig. 5, ‘Crag Moll.’) is possibly a var. of reticosa. 
T have not been able to find another like it. 
Nassa LaBiosa, J. Sow. Crag. Moll., vol. i, p. 28, Tab. VII, fig. 22. 
This shell was by E. Forbes referred to Buc. semistriatum, Broc. (Mem. Geol. Surv.,’ 
1846, p. 428), and lately by Mr. Jeffreys, ‘Geol. Journ., vol. xxv, p. 144. I still 
think the two shells specifically distinct for the reasons stated at the above reference. 
