212 MESSRS. A. S. KENNARD AND B. B. WOODWARD ON THE 



Miiller. Mailer includes in his synonymy (Verm. Hist. ii. p. 1G0) the 

 Helix complanatus of Linne, but three pages further on queries whether the 

 latter be not the same as his own P. nitidus, a point we discuss later. 



Linne's name for this species having priority must be restored to literature. 



Planorbis (Nautilus then Turbo, L.) crista. 



Despite Linne's doubt as to the zoological position of this form, referring 

 it as he does first to Nautilus and then with the changed trivial name of 

 nautileus to Turbo, there never has been any hesitation as to the species 

 meant. 



Planorbis (Helix, L.) vortex (1). 



The figures referred to in Lister and Gualtieri show clearly the group to 

 which Linne's species belongs, and the description in the 'Fauna Svecica' 

 (2nd ed., p. 527, no. 2173), "margo testse in ilia extra test-am exseritur, at in 

 hac ipse testse angulus est acutus," points to the correctness of the accepted 

 interpretation, which is further borne out by the single example in the 

 collection. 



Planorbis (Helix, L.) spirorbis. 



No figures are cited by Linne and the description is rather too vague to 

 enable one to accurately discriminate the species. Linne's specimen must 

 have been bleached since it is given as " Testa alba." No example is in the 

 collection. 



Midler, who adopts the species (Verm. Hist. ii. p. 161), further defines 

 it as having " anfractus quatuor .. . margine tereti absque ulla carina. 

 Apertura rotnndata sublabiata ; margo saltern summus intus albus, crassius- 

 culus." This seems to indicate the commonly accepted species. The closely 

 allied rotundata, Poiret, has a whorl more and a more angular mouth. 



*Planorbis (Helix, L.) contortus. 



Although no figures are cited, the description in the ' Fauna Svecica ' 

 (2nd ed., p. 528, no. 2181) and the former presence, vouched for by Hanley, 

 of a specimen in the collection, that, however, we have not seen, serve to 

 establish the identity of this species with the commonly accepted form. 



Planorbis (Helix) complanatus. 



Hanley's arguments and conclusions concerning this species are correct, 

 given the fact that he in common with most other observers of his period 

 identified Miiller's nitidus with Lightfoot's/onta/tus, whereas it is now known, 

 and we have the authority of Dr. A. C. Johansen for the fact, that all 

 Miiller's specimens belong to the form called lacustris by Lightfoot and 

 placed to-day in the genus Segmentina of Fleming. Some of Miiller's 

 specimens are not, Dr. Johansen states, well preserved and this led 



