158 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Sardinian section Ichnusarion, Poll. ; there is but slight difference in 

 the sexual apparatus between A. Isselii, Bgt., and A. Austriacus, 

 nevertheless its external characters and its habitat show the latter to 

 be distinct. Were the structure of adult individuals of Ariunculus, 

 Less. (Poll.), s.str., known (half-grown animals oi Ariunculus Ilortilleti, 

 Less., were, it is true, dissected by Simroth [3] ), better reasons for 

 this contention would undoubtedly be forthcoming. 



Our knowledge (small enough, certainly) of the anatomy of this group 

 of Palsearctic Arionidae (founded on the descriptions of Ariunculus 

 furnished by Lessona [1], Pollonera [4], and Simroth [3], and of 

 Letourneuxia by Hesse [2], Pollonera [4], and Simroth [5] ), tends to 

 confirm the opinion of Simroth [5] that Pollonera [3] was wrong 

 in assigning Letourneuxia, Bgt., to the genus GeomaJacns, Allm., 

 when it is manifestly much more nearly allied to Ariunculus, while 

 Geomalacus stands apart amongst the Arionidae. 



Bibliography. 



1. Lessona, M., & Pollonera, D., " Monografia dei Limacidi italiani " : 



Mem. Ace. Sci. Torino, ser. ii, tom. xxxv (1884), pp. 49-128, 

 3 pis. 



2. Hesse, P., " Nacktschnecken von Tanger und Gibraltar " : 



Malakozool. Blatter, n.e., vol. vii (1884), pp. 9-17. 



3. Simroth, H. P., " tjber bekannte palaearctische N^acktschnecken " : 



Jahrb. Deutsch. malak. Ges., Bd. xiii(1886), pp. 311-342, 2 pis. 



4. Pollonera. D., " Recensement des Ariotiidee de la Region 



Palearctique " : Boll. Mus. Zool. Aiiat. comp. Torino, 

 tom. V (1890), No. 87. 



5. Simroth, H. E., " Uber die Nacktschnecken der Azorisch-Portu- 



giesischen Fauna " : Nova Acta Acad. Cses. Leop. Carol., 

 tom. Ivi (1891), pp. 201-424, 10 pis. 



6. CoLLiNGE, W. E., " The Myology of some Pulmonate Mollusca 



considered as a distinctive feature in the discrimination of 

 Genera, etc." : Proc. Malac. Soc. Lond., vol. i (1894), 

 pp. 52-54. 

 [See also these Proceedings, ante, p. 94, Pilsery, H. A., " Phylogeny 

 of the Genera of Arionidae."] 



