ScHARFF — The Slugs of Ireland. 193 



Uuder the heading of each species mentioned in this Memoii', 

 are paragraphs dealing with — 1. External characters. 2. Ana- 

 tomy. 3. Reproduction. 4. Habitat. 5. Food. 6. Greneral 

 Distribution. Neither the shell nor the radula (or tongue) are 

 mentioned, as they do not afford such easy and reliable evidence 

 in the identification of the species as the reproductive organs. 

 Figures of the latter are given for every species. 



The thirteen species of Irish slugs belong to five genera, viz. 

 Limax, AgrioUmax, Amalia, Arion, and Geomalacus. The species 

 of the three first genera can be very readily discriminated from 

 those of the genus Arion, by the absence of the caudal gland. 

 This gland is present in Qeomalacus, but it is not nearly so conspi- 

 cuous as in Arion, in 'which its triangular opening at the end of 

 the body is vv^ell seen. 



Besides the characteristic just mentioned, the pulmonary opening 

 in Limax, Agriolimax, and Amalia is situated behind the middle of 

 the mantle. These three genera can again be separated into 

 Limax and Agriolimax, both of which have a mantle with concen- 

 tric wrinkles, and Amalia, in which the mantle is granulated 

 instead of being wrinkled. 



It is more difiicult to find reliable external characters by which 

 to separate the genera Limax and Agriolimax. However, in all 

 cases, the young Limax possesses a dark band or row of spots along 

 the side of its body, while in Agriolimax dark bands are quite 

 absent, and when spots are present, they are scattered over the 

 body, and not in regular rows. 



In the slugs possessing a caudal gland, viz. Arion and Geoma- 

 lacus, the pulmonary opening lies in front of the middle of the 

 mantle, which distinguishes them easily from the preceding genera. 



Three species of Limax are found in Ireland, and these are 

 readily recognisable externally by the markings on the mantle. 

 Thus the mantle (or shield covering the front portion of the slug's 

 body) is either light with darker spots, or uniformly dark in L. 

 maximus (L.). In the next species, viz. L. flavus (L.), there are 

 lighter spots on the darker and generally yellow mantle. In L. 

 marginatus (M tiller), the third Irish species of Limax, the mantle, 

 as in L. maximus, is light in colour, but instead of spots there 

 is a very distinct dark band on each side of it. 



There are two Irish species of Agriolimax. In A. agrestis the 



