n6 collinge: structure and affinities of European slugs. 



Arion alpinus, Pollonera. 



Locality : Rivarossa, Piemont. 



When Pollonera first described this species I had many doubts 

 as to whether it was not a young form of A. hortensis. The specimens, 

 however, which he has so generously sent me, have enabled me to 

 make a very careful examination of the internal structure, from which 

 I am inclined to support its specific distinction. 



The ruga; of this species are interesting, and quite unlike those 

 of any other Arion I am acquainted with. They are small, flat (?) 

 and oblong, and arranged in distinct longitudinal rows. 



Arion fasciatus, Nils. 



= A. bourguignati) Mabille. 



Var. miser, Pollonera. 



These specimens are from the Vallie du Grand St. Bernard. 

 They show a prominent keel, and a distinct lateral band continued 

 along each side of the mantle. 



Var. neustriacus, Mabille. 

 From Rivarossa. Similar in all respects to our British specimens. 



Arion lusitanicus, Mabille, 186S. 



Arion ru/us, Morelet, Descr. Moll. Port., 1845, p. 29. 



Ari<>ti lusitanicus, Mabille, Rev. et Mag. Zool., 1868, p. 134. 



Arion lusitanicus, Pollonera, Nuove. contrib. a. studio d. Arion 

 eurqpei, 1SS9, p. 405, figs. 1-6. 



Arion lusitanicus, Simroth, Die Nachtschnecken d. Port. Fauna 

 1 89 1. 



Arion lusitanicus, Collinge, Review of the ArionidcB of the Brit. 

 Is., 1S92, p. 7. 



I have previously recorded this slug as a British species. At 

 the request of a number of malacologists I am giving a description 

 of what could be made out from the spirit examples I had. Possibly 

 these will require some slight corrections when fresh material is 

 examined. 



A. lusitanicus ma)' at once be distinguished from A. empiricorum, 

 Fer., from the fact that it has only a single vestibule leading from 

 the generative orifice. The vas deferens is unusually long and exhibits 

 a distinct differentiation between the upper and lower portions. 

 The retractor muscles are attached to the lower portion of the 



