VII. 

 ox TEE OCCURREXCE OF VERTTGO MOULINSIANA, DUPUY, 



IN HEKTFORDSHIllE. 



By Hei^ry Geoves. 



Communicated by J. Gwyn Jeffreys, LL.D., F.E.S., President. 



Read at Watford, 2Qth Jannari/, 1880, 



Plate I.* 



Dr. Gwyn Jeffreys has suggested to me that a few remarks upon 

 the occurrence of Vertigo Moalinsiana in Hertfordshire would be 

 interesting to the Society. 



This rare mollusk is one of the largest of our British species of 

 Vertigo (although it is less than an eighth of an inch in length) ; 

 and it is by far the largest of those which have teeth or plications 

 in the mouth of the shell ; it is equalled in size by the toothless 

 species V. edentula. V. Moulinsiana may be readily distiuguished 

 from the allied species V. piigmma by its larger size and much more 

 swollen whorls. It usually occurs in company with V. antivertigo, 

 which differs from it in its darker colour, and by having from 

 eight to nine instead of four or five teeth. The name V. Moulins- 

 iana, given by the Abbe Dupuy, has been adopted by Dr. Gwyn 

 Jeffreys in his work ' British Conchology.' 



Vertigo Moulinsiana is distributed over ceutral, western, and 

 noi'th-western Europe. Dr. Gwyn Jeffreys has recorded its occur- 

 rence in Carinthia, Sweden, Denmark, western Germany, the north, 

 west, and south of France, and Switzerland. It was added to our 

 list of English species in 1877, in which year it was collected by 

 my brother and myself in Hampshire. The locality in which we 

 first found it was in a small boggy marsh in the Itchen Valley, near 

 Otterbourne, and within a short distance of Bishopstoke. I next 

 found it in the neighbourhood of Hitchin, in the broad marshy 

 margin of the river which flows through the moorland known as 

 Oughton Head. I afterwards found it near the Essex border of 

 Hertfordshire whilst shell-hunting last autumn in company with 

 Dr. Gwyn Jeffreys and Mr. Rimmer, in a large marsh by the side 

 of the Cambridge line of the Great Eastern Railway, just where it 

 crosses the River Lea, a short distance below Rye House ; since 

 then I have found a new locality for it in Hampshire, about a mile 

 from that previously mentioned, and a short distance below Bishop- 

 stoke, where it exists in great numbers and comparatively of a large 

 size. 



The point which I wish particularly to make clear is the habitat 

 in wbich this mollusk should be looked for. The localities in which 

 I have found it are very wet marshes, and the swampy margins 

 of rivers and ditches, along with such y)lants as Carex paniculataj 

 C. paludosa, C. riparia, Jimcus, Iris, Typha, Phragmites, and other 



* From drawings by the author of a specimen of Vertigo Moulinsiana found 

 by him near Hitchin. The mark -\- indicates the natural size. — Ed. 



VOL. I. — PAKT U. 6 



