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A PECULIAR FORM OF HYGROMIA FUSCA (Montagu) FROM 

 LEIGH WOODS (SOMERSET), NEAR BRISTOL. 



By D. BACCHUS. 



(Read before the Society, March 2nd, 1921). 



During the autumn of 1920 Mr. Kennard mentioned in a letter to 

 me that he required some H. fusca from the West of England. On 

 receipt of this letter I paid a visit to a bank, where I generally 

 manage to find some half dozen or more H. fusca each time 

 I visit it. On the result of my catch being received by Mr. Kennard, 

 he immediately asked if I would send some on alive to Mr. Hugh 

 Watson, of Cambridge, for dissection as they were "totally unlike 

 fusca from the North." I sent some twenty living examples to 

 Mr. Watson who says in reply : " The shells differ considerably from 

 what I take to be the normal form of the species such as one finds in 

 the North of England. They are darker in colour and not so thin, 

 slightly larger and have more slowly increasing whorls and a smaller 

 mouth. A preliminary dissection shows that the reproductive organs 

 are very like those described and figured by Taylor in his account of 

 fisca, and the radula agrees closely with Bowell's figure. On the 

 other hand, the colouration of the animal differs from Taylor's 

 account." Shells collected by Mr. Watson some years ago from Leigh 

 Woods and at Plymouth are more depressed than either my specimens 

 or the type, though in some respects they are intermediate. 



Fusca from South Devon and Glamorgan in my own collection, 

 Mr. Watson informs me, are intermediate between the Leigh Woods 

 specimens and those from Northumberland. Specimens taken, how- 

 ever, by Mr. Swan ton some years ago in East Somerset, are without 

 any trace of rufous colouring and very thin. 



In a second letter Mr. Watson says, " It is not unlikely that your 

 Leigh Woods examples may prove to be nearer the type of the species 

 than the northern form which I have always looked upon as the 

 ordinary fusca, for Montagu's original specimens came from the South 

 of England, and it was from shells found near Bristol that Miller 

 established his II. subrufescefis, the name by which the priority purists 

 now wish fusca to be known." Montagu describes the shell of the 

 type as thin, pellucid, rufous, horn-coloured, and adds that Mr. Boys 

 of Sandwich, favoured him with this species. Mr. Swanton, who 

 informed me of the above description of Montagu, says of my speci- 

 mens, " at first sight they almost suggest a cross between fusca and 

 hispida." This is undoubtedly true: even under a lens I have 

 repeatedly had to turn them over to see if it is fusca or a var, depilata 

 of hispida from the same bank. 



