144 AGARDH1A. 



a single specimen in deposit F, of a short, thick-set variety 

 (var. tumida), probably enough a distinct species. Typical 

 Pupa biplicata Mich, and P. ressmani Villa are the nearest 

 forms I know to P. bourguignatiana; from both the present 

 species can be told at once by the above-described characters 

 of the aperture. A specimen from Tuscany which I obtained 

 from Madame Viment at Paris, labelled P. biplicata, is a 

 totally distinct species from the Menton one ; it is the P. tosca- 

 nice of Bourg. (Nevill). 



A. ligustica (Poll.) appears to be a living representative of 

 this Pleistocene form, probably not specifically distinct. 



The deposits in which the Menton shells are found have 

 been described by Nevill as follows: 



A. Alpes-Maritimes, a few yards only from the Italian 

 frontier, a stone's throw from the "Pont St. Louis," esti- 

 mated about 50 yards above the sea, in a deep cutting of the 

 high road under the larger boulders about the level of the 

 road, buried beneath approximately 20 ft. of conglomerate. 



B. Underneath the railway viaduct, almost exactly in front 

 of the first cavern, something like 100 metres west of the 

 tunnel, and about the same distance east of the Gorge St. 

 Louis (frontier), about 20 meters above the sea. After pass- 

 ing through the arches one finds before one a small amphi- 

 theatre, in which these shells can be found here and there in 

 astonishing profusion. 



C. Deposit, with a southern aspect, a little more to the 

 east than the preceding and somewhat lower down, a few feet 

 only above the sea, in a cutting of the new road which is being 

 made along the seashore for working a stone-quarry, on the 

 sea front of the tunnel. The conglomerate, above the shells, 

 was here about 20 to 30 feet in thickness. I am not sure that 

 the mollusks lived on this spot. 



D. Deposit, with a northern aspect in a cutting of the rail- 

 road about a quarter of an hour's walk to the east from the 

 preceding, about a hundred yards east of the tunnel. 



In these deposits the shells are mainly found under large 

 rocks. 



Nevill defined five varietal and subvarietal forms of A. 

 bourguignatiana, three of which he thought might be species. 

 That so many closely related races existed in this very limited 

 area seems unlikely; a wide swing of individual variation 

 appears more probable. The group of forms is known to me 



