i2c 



V IT BIN A MAJOR IN BRITAIN. 

 By Dr. A. E. Boycott, F.R.S. 



Read ISth May, 1922. 

 On 22nd April last, while searchiiig for Azeca tridens in Cusop Dingle, 

 near Hay, among stones and dead wood on a mossy bank, about 

 6 feet on the Breconsliire side of the stream, wMch here forms the 

 Herefordshire boundary, I picked up a Vitrina, which on subsequent 

 examination appeared to be new to the British fauna. In a straight 

 line on the map the sf)ot is about 4,200 yards south-east of Hay 

 Railway Station. This upper part of the narrow Cusop valley is 

 wild, semi-cultivated land, and the valley soon runs out above on 

 to the open moor of the Black Mountains. There are two or three 

 small hill farms in the neighbourhood. The land around the stream 

 is rough, open scrub, used for grazing, with a good many wet 

 boggy places. It lies on the Old Red Sandstone, and the locality is 

 apparently moderately calcareous ; there are a number of ash-trees, 

 and close by the remains of an old lime-kiln. Besides the Vitrina, 

 a short search yielded Limax maximus, Agriolimax agrestis, Arion 

 ater (black, red, and chocolate forms), A. subfuscus, A. hortensis, 

 A. circumscriptus, Vitrina pellucida, Hyalinia cellaria, H. alliaria, 

 H. nitidula, H. pura, Vitrea crystallina, Conulus fulvus, Punctum 

 pygmceum, Pyramidula rotundata, Hygroma hispida, Helix nemoralis, 

 H. hortensis, Arianta arhustorum, Azeca tridens, Cochlicopa luhrica, 

 and Carychium minimum ; the place is evidently favourable to 

 molluscan life. 



During life the new Vitrina was not examined with as much care 

 as it deserved. • The shell seemed rather flat, the animal was very 

 dark-coloured, and it crawled about with unusual vivacity — 

 characters which by a lucky chance made me curious enough to 

 examine its anatomy along with that of two other specimens of 

 Vitrina more closely resembling pellucida, which were taken at the 

 same time. It may be said at once that these latter corresponded 

 in all respects to V. pellucida in shell, genitalia, and radula. The 

 genitalia of the other, however, showed at once that it was neither 

 pellucida nor the Irish species called pyrenaica or hihernica ^ 

 (Fig. 1 A-c). The feature which attracts attention is the presence 

 on the oviduct of a large, globular, hard, glistening swelling, partly 

 enveloped in its upper part, i.e. away from the genital orifice, with 



^ There seem to be no good reasons for separating the form first found by 

 Mr. P. H. Grierson in Co. Louth from the French form known as pyrenaica, 

 but it should be clearly understood that in talking of " pyrenaica " I am 

 referring to Irish specimens. These do not seem to differ from pickled specimens 

 of pyrenaica from Pau which Mr. H. Watson kindly gave me. See J. W. 

 Taylor, Irish Naturalist, xvi, 1907, p. 225, Monograph, pt. xv, 1908, p. ii of 

 cover, vol. iii, 1914, p. 449 ; E. W. Bowell, Irish Naturalist, xvii, 1908, p. 94, 

 xxiii, 1914, p. 210 ; A. E. Boycott, Irish Naturalist, xxiii, 1914, p. 205. 



