ADAMS: ON SOME BRITISH LAND AND FRESHWATER SHELLS. 



30I 



Fig. 4. Geomalacus 

 maculosus, rolled up. 



Geomalacus maculosus Allman. — I have noticed with much 

 interest that the light spots which besprinkle this slug are not scattered 

 indiscriminately, but are in all cases less numer- 

 ous in the regions of the lateral and dorsal bands 

 which exist in other slugs. This is much more 

 noticeable in juvenile specimens than in adults — 

 the smaller the individual the clearer the bands. 

 This species has the habit of curling up into a 

 perfect sphere, when irritated, after the manner 

 of a woodlouse (see fig. 4). 

 I would call attention here to the Irish slugs as a whole. They are 

 much more variable in colour than those met with in Great Britain. 

 This is especially the case with Limax marginatus Miiller (= L. 

 arbnslorwn B. Ch.), Limax maximus L., and Avion aier L. In Ire- 

 land the very young of A. ater (especially the form biunnea) are 

 commonly banded, whereas in Great Britain this is very exceptional 

 except in South Wales. Certain strikingly coloured forms are common 

 in Ireland which are exceedingly rare here, though in South and Mid 

 Wales I have come across them in large colonies. The same remark 

 applies to L. maximus, though to a less extent. On the whole the 

 greatest number of varietal forms is found in the S.W. of the British 

 Isles, and the fewest towards the N.E. And this is exactly what we 

 should expect if we accept the theory of a Lusitanian origin of our 

 slugs which has been so ably set forth by Dr. R. F. Scharff in his 

 " European Fauna." 



Carychium minimum Miiller. — Jeffreys' description of this animal 

 does not quite correspond with my observations, and his figure (the 

 only one, so far as I am aware, in any British work) is decidedly faulty. 

 He describes the ends of the tentacles as ' rounded,' and he figures 

 them with rounded bulbs. In all the many specimens I have examined 



Fig. 5. Two views of Carychium minimum. 



the tentacles are simply conical, and Moquin-Tandon's figure exactly 

 corresponds with my drawings in this respect. The position of the 

 conspicuous sessile eyes is close behind the bases of the tentacles, and 



