302 JOURNAL OF CONCHOLOGY, VOL. 9, NO. IO, APRIL, I9OO. 



not between them, as figured by Jeffreys ; and moreover, they consist 

 of simple black spots with no surrounding ring (see fig. 5). I once 

 took an individual in North Ireland which had no right eye, though 

 normal in other respects. I have never been able to perceive the 

 " black and white speckles " which Jeffreys speaks of as occurring on 

 the footsole. 



White forms of Pupa cylindracea Da Costa, P. anglica Ferussac, 

 P. Muscorum L, Acicula lineata Draparnaud. — It is commonly 

 supposed that the white varieties of mollusks are albinos, which is far 

 from being always the case. As Mr. K. H. Jones points out in his 

 article on Albinism, 1 individuals with any particle of pigment even in 

 the eye alone, though possessing perfectly white shells, are not true 

 albinos. An extensive examination of the white forms of the above 

 species shows that not one of them is a true albino, indeed all the 

 white Puptz have nearly as much body colour as their types. 



Acicula lineata, however, is perfectly colourless and 

 transparent like C. acicula, but the rows of pigment 

 dots which constitute its sessile eyes show that it is 

 no more a true albino than C. minimum. These eye- 

 dots can be seen quite plainly through the shells of 

 both the type and the var. alba (see fig. 6). 



FlG 6 True albinism in our British non-marine shells is 



Acicula lineata, extremely rare, the only constant specific instance 



iTenf spots' 2 being C. acicula. The only instances of varietal al- 

 though the shell, binism that have come under my notice are a single 

 specimen of Limax maximus L., and two specimens of Agriolimax 

 agrestis L. 



It is easy to understand how an animal though possessed of body 

 colour, should fail to secrete colouring matter for the shell, but it is 

 not so easy to understand how an animal perfectly colourless itself 

 should possess a normally coloured shell. An example of this anomaly 

 occurred a few years ago in an adult Helix aspersa which I found at 

 Dover. The animal was perfectly white, even the eyes being colourless, 

 while the shell was slightly darker than usual. 



1 /. Conch., vol. 8, p. 3. 



Helix marmorata var. alba nov. — This form of Helix marmorata has not 

 previously, so far as I can ascertain, been described. The shell is white with trans- 

 lucent markings. Although this species exists in countless thousands at Gibraltar 

 where my albino specimen was taken in November, 1898, it is the only example of 

 this variety revealed during many weeks of careful research. — K. Hurlstone 

 Jones {Read before the Society, March 14th, 1900). 



