58 PALUDINIDiE. 



2. P. vivi'pARA"^, Linne. 



Helix vivipara, Linn. Syst. Nat. ed. xii. p. 1247. P. vivipara, F. & H, 

 iii. p. 11, pi. Ixxi. f. 14, 15, and (animal) pi. H. H. f. 2. 



Boot of a darker colour than that of P. contecta : snout 

 broad: tentacles bluish-black, with bright yellow spots; the 

 difference of their size in the male being very perceptible : eyes 

 rather large : foot very broad, and slightly truncate in front. 



Shell oval, rather solid, but not so glossy as that of P. con- 

 tecta, yellowish-gTeen, mth bands and striae as in that spe- 

 cies ; the surface of the two last whorls is often iiTegularly 

 indented or pitted : ejndermis rather thin : whorls 6|, rather 

 convex, the last exceeding one-half of the shell, gi-adually in- 

 creasing in size, except the first, which is extremely small and 

 twisted, but much less prominent than in the last species, 

 making the point of the spire to appear blunt : suture rather 

 deep : mouth oval, and less inchned to a circular shape than in 

 P. contecta : outer lip rather thick and slightly reflected : inner 

 lip united above to the columella, but both lips form a com- 

 plete peristome : there is no umbilicus, but instead of it there 

 is a small and narrow chink behind the inner lip : operculum 

 rather thick, compressed transversely, and marked with strong 

 lines of increase and finer intermediate striae. L. 1*5. B. 1-2. 



Var. unicolor. Without bands. 



Habitat : The same as that of the last species (with 

 which it is often found living), except that the Rev. Dr. 

 Gordon has found it at Findhorn in the Moray Firth 

 district. Sir Charles Lyell has recorded its occurrence 

 in the lacustrine deposit at Mundesley in Norfolk. Its 

 northern range abroad is also the same ; but it extends 

 southwards to Naples, and (according to Philippi) pro- 

 bably also to Sicily. The variety has been found by 

 Mr. Pickering in Hertfordshire, and by myself in the 

 Thames at Richmond. I have also a monstrosity in 

 which the last whorl has a keel occupying the place of 

 the upper band. 



This species differs from P. contecta in its shell being 



* Bringing forth its young alive and perfect. 



