304 



A FURTHER NOTE ON PIGMENTATION IN 

 HELICELLA GIGAXII. 



By a. E. boycott and J. WILFRID JACKSON. 



(Read before the Society, Jan. 13th, 1915). 



In answer to our request for live specimens of H. gigaxii (antea 

 p, 167), we have received the following lots : — 



No. I. — Hudnall Common, near Berkhamsted, Herts. From 

 Mr. C. Oldham. A small form, of drab colour ; some distinctly 

 banded, especially below the periphery ; others with broken bands, 

 small blotches or flames ; a few entirely bandless (=var. lutescens^ 

 Kendall). From this locality Mr. Oldham has also recently de- 

 scribed some specimens as var. hyalozonata. Average diameter=7mm. 



No. 2.— Little Tring, Herts. From Mr. C. Oldham. A slightly 

 larger form, showing the same variation in colour and marking as 

 No, I, and including vars. hyalozonata and alba of Oldham. 

 Average diameter=8mm. 



No. 3. — Wendover, Bucks. From Mr. C. Oldham. A larger 

 form, banded and blotched as No. i ; also vars. hitescens, Kendall, 

 and hyalozonata, Oldham. Average diameter=io mm. (Largest 

 specimen=i2mm.). 



No. 4. — Ayton Road, near Scarborough. From Mr. Hargreaves. 

 A medium-sized form, banded, blotched, and unicolorous (var. 

 Intescens). Average diameter=8"5 to gmm. 



No. 5. — Portsdown Hill, Hants. From Mr. H. Beeston. A very 

 small form, comprising white shells (like var. alba, Oldham) ; 

 whitish shells with dark apex (like var. albicans, Kendall) ; whit- 

 ish shells minutely and sparsely speckled or blotched, some- 

 times banded below the periphery. This is a remarkably small 

 form and quite full-grown. The average diameter=6'5 to 7 ; largest 

 =8"9mm.. Mr. Beeston writes, "they never grow any larger. The 

 habitat is among the very short grass on the highest and driest 

 parts of the downs, and in dry weather they are almost indistinguish- 

 able from the tiny pieces of white chalk." 



In the above five lots the pigmentation of the genitalia pre- 

 viously found to be characteristic of the H. gigaxii from Prestatyn 

 was present, i.e. the neck of the dart-sac and the lower part of the 

 duct of the spermatheca were darkly pigmented, the latter being 

 often black. Lot 5 were examined pretty thoroughly, but no clear 

 difference from the others could be made out ; the mucous glands 

 were more voluminous and bulbous, but their precise shape and 

 arrangement is variable. 



