282 Mr. T, D. A, Cockercll's Notes on Slugs. 



IT. The Tandonia Section of Alalia. 



The keeled slugs, referred by modern authors to the genus 

 Amah'a, Moquin-Tandon, were divided by Lessona and 

 Pollonera in 1882 into groups — Pirainea, the group of -4. 

 gagates^ and I^ANDONIA, the group of A. cai-inata and A.mar- 

 ginata. A third group, having an incomplete keel, is Mali- 

 nastrum, Bourg. { = Subamah'a, Poll, 1887). The Tandonia 

 section is credited by Pollonera with twelve species, but 

 several of them are very closely allied — not more distinct, 

 indeed, than other races almost universally considered varieties. 

 Probably the number of species will be greatly reduced when 

 it becomes possible to compare living examples and dissect 

 fresh specimens of all of them. 



I give here a list of the recorded forms, with notes : — 



Amalia marginata (Drap.). 



Known by its small spots and banded mantle. There is a 

 specimen in the British Museum from Waldeck, received 

 from Dr. Heynemann, from which I made the following 

 notes : — 



25 millim. long (in alcohol), narrower than car/??a/a, and 

 hardly arched. Sole ochrey ; median area hardly twice as 

 broad as one lateral area. Keel straight, ochreous, Body 

 ochreous at sides, bluish grey dorsally, with a peppering of 

 dark grey points all over (except under mantle and on sole). 

 Mantle with lateral dark bands fading away anteriorly. 



This is quite a distinct species and quite different from the 

 English slug, carinata, Leach, usually called marginata. I 

 have never seen an English example of true marginata^ nor 

 can I find any evidence of its occurrence in the British 

 Islands by searching the literature. The figure and descrip- 

 tion by Rimmer (Land and Freshwater Shells of British 

 Islands, 1880) belong to the true marginata, but they are 

 copied apparently from the French, and have actually no 

 reference to an English slug. Heynemann (Die nackt. 

 Landpulm. des Erdbodens, 1885) gives A. marginata as 

 British, but he was probably misled by British authors. 

 Roebuck (' Science Gossip,' 1884, p. 78) records var. rustica 

 from Gloucestershire ; but it is probable — I think practically 

 certain — that he had not the true rustica^ Mill., as understood 

 in France''^, but a variety of ^. carinata. 



* Kreglinger, 1870, gives rusticus, Mill., as a 8ynonym of Z, {Lehinan- 

 nia) maryinatus, Mull. 



