228 ARIONDLE. 



ratory aperture, and, in place of a regular shell, there are 

 merely a few calcareous granules forming a small mass in 

 the interior of the mantle. The Arions or "Land-soles" 

 as they have been termed, are more dull in their habits than 

 the True Slugs, from which they are readily distinguished on 

 account of their glanduliferous tail. The genus is repre- 

 sented in Europe and South Africa, and is found in Bri- 

 tain, Spain, and the Island of Ascension. 



Species of Avion. 



Ascensionis, Quoy and Gaim. furcatus, Ferns. 



ater, Linn. hortensis, Ferns. 



flavus, Mull. lactescens, Blainv. 



foliolatus, Gould. subfuscus, Drap. 



Genus GEOMALACUS, Allman. 



Animal slug-like. Eye-peduncles moderate. Mantle 

 shield-shaped, on the fore part of the back ; orifice of respi- 

 ratory sac at the right anterior margin. Genital aperture near 

 the root of the right eye-peduncle. Tail rounded above, 

 truncate posteriorly and furnished with a mucous gland. 



Shell internal, solid, flat, ovate. 



Ex. G. maculatus, Allman, pi. 80, fig. 4. Shell, G. 

 maculatus, fig. 4, a. 



This genus differs from Arion in the position of the gene- 

 rative orifice, and in having a solid, testaceous shell ; from 

 Limax it is at once distinguished by its glanduliferous tail, 

 and by the anterior position of the breathing aperture. The 

 Geomalacus is a native of Ireland, where it lives in damp 

 places, among loose stones and ferns. The Authors are in- 

 debted to the kindness of Mr. Andrews, the first discoverer of 



