ARIOX ATER, VAR. ATERIilMA, BLACK, PARTLY EXTENDED. 



BRITISH SLUGS— II 



By MAUD U. CLARKE 

 With Photographs by the Author 



ARIOXID.E 



THIS class of Slugs present very dis- 

 tinct differences of character from 

 the Limacida, and as represented 

 in the British Isles are subdivided into the 

 two groups of Avion ater and Geomalaciis. 



The shell is reduced to some coagulated 

 grains of calcareous pulp l>ing within the 

 shell-sac beneath the hinder part of the 

 " shield." When exposed to the air 

 the grains harden, the condensation vary- 

 ing to some extent with the age of the 

 animal. The body is rounded and stout, 

 the skin-folds being cut and recut into 

 coarse elevations. The " shield " has an 

 indt-nted or granulated surface quite 

 unlike the ringed hnes of Limax, and shows 

 the respiratory orifice on the right anterior 

 border of the " shield " nearer to the 

 neck of the animal than the last-named 

 species. 



These two points of difference are easily 

 to be decided in looking at the slug, and 

 show to which of the two classes a 

 specimen belongs. 



The " foot-sole " is white or hght with 



few exceptions, and shows a distinct pedal 

 groove ; the " foot-fringe " is sometimes 

 noticeable as a distinct variation in 

 colour from that of the body, as in the 

 greenish-grey variety that has an orange 

 " foot-fringe." This muscular border is 

 further accentuated with fine black trans- 

 verse hnes. 



This slug is nocturnal in habit, liiding 

 from heat during daytime, and only 

 emerging in cool, wet weather. 



After days of drought in summer when 

 rain threatens we often see black speci- 

 mens of Arion at full stretch, travelling 

 over the roadside grass after leaving 

 their quarters in the ditches. They are 

 voracious feeders, but their length of Ufa 

 is not estimated as over a year. Compared 

 with Limax they are feeble in recuperative 

 vitality, easily succumbing to injuries. 

 A black Arion died within a few hours 

 after a fall of eighteen inches upon a 

 deal table, whereas a specimen of Limax 

 maximus fell a height of five feet upon 

 a gravel path, and seemed none the worse 

 for it. In temper, I should regard the 

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