LINXEAN SPECIES OF BRITISH NOW-MARINE MOLLTJSCA. 211 



pereger. " Klein ostr. 54. t. 3. f. 69 " is a bad copy of the figure in Li.-ter's 

 ' Hist. Anim. Angl.' pi. ii. f. 21 (and is Klein's type of his Auricularia 

 stagnorum) or the figure already cited by Linne as his Helix stagnalis. The 

 "Acta Helv. 5. t. 3. f. 27, 28" is evidently auricularia. 



The specimens in the collection include auricularia vera (3) and inflated 

 forms of pereger (4). Midler's segregation of the latter is therefore correct. 



Helix limosa. 



Nilsson (p. 72) identified this with Limncea truncatula (Midi.), whilst 

 Hanley (p. 387) conjectures it may have been a narrow form of L. pereger 

 (Mull.) and Reeve (Land & Fresh- w. Moll. Brit. Is., p. 157) adopt the name 

 for that species. 



The figure cited by Linne in the 12th edition of the 'Systema' (p. 124'.)) 

 from Gualtieri (pi. v. f. H) and marked on the margin of the plate in his 

 own handwriting, is suggestive of the fry of possibly Succinea putris. In 

 the 'Fauna Svecica' first edition (p. 367. no. 1314) it is described as 

 " anfractibus quinque," an item omitted in both the 10th and 12th editions 

 of the 'Systema' ; whilst the final "Descr." reads " Prsecedentibus dnabus 

 duplo minor ; operculo etiam clauditur." 



The two preceding species of the 1st edition of the 'Fauna' are named 

 in the 2nd Helix vivipara and Helix tentaculata. Linne's Helix limosa was 

 therefore an operculatef, which cannot now be identified, so that the name 

 must be allowed to lapse. 



Helix balthica. 



The " rugis elevatis " noted in the description of this species (Fauna Svec. 

 2nd ed., p. 532) and amplified in the "Descr." to "superficies testse striis 

 elevatis remotis versus apertura? marginem oblique descendentibus " does not 

 accord with a Limncea, to which genus Nilsson (pp. 64-65) refers it. 



The form appears indeterminate and likely to remain so. 



*Limn.s:a (Helix, L.) stagnalis (1). 



By diagnosis and figures the identity of this species is confirmed. Also 

 that Linne's H. fragilis is a synonym. 



*Planorbis (Helix, L.) cornel's (4). 



This is, fortunately, one of those species concerning whose identity there 

 never has been any doubt. 



*Planorbis (Helix, L.) planorbis (8, including 3 probably sent by 

 Miiller as examples of his P. umbilicatus). 



Why there should have been any question concerning this form it is 

 difficult to understand, for the reference to Lister's figure (Anim. Angl. 

 pi. ii. f. 27) clearly establishes its identity with the Planorbis umbilicatus of 



t This we find has already been pointed out by MSrch (Synop. Moll. Daniie, 1864, p. 43, 

 note). 



