GASTEROPODA. 15 



Nassa reticosa, /. Sowerby. Crag Moll., vol. i, p. 33, Tab. Ill, fig. 10 ; Supplement, 

 Tab. IV, fig. 3, and Tab. VII, fig. 15. 



Localities. Red Crag passim; Chillesford bed, Easton 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. simplex, 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. scalarina. ■ 



Mr. Bell informs me that he has obtained N. 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 conglobata, Broc. {' Crag. Moll.,' vol. i, p. 32, Tab. Ill, fig. 9), is possibly 

 Buccinum [Besmoulea) abbreviation, 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, Eorbes, and N. Pliocena, 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. Ill, fig. 5, ' Crag Moll/) is possibly a var. of reticosa. 

 I 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. xxvii, p. 144. I still 

 think the two shells specifically distinct for the reasons stated at the above reference. 



