236 JOURNAL OF CONCHOLOGY, VOL. 12, NO. 9, JANUARY, I9O9. 



fringe, ten were referable to var. rufa, and two to var. castanea. Of 

 this second generation, the var. riifa was paired with the var. castanea, 

 and fourteen eggs were hatched and reared to maturity. Of these 

 fourteen, four were typical of the species, eight were referable to 

 var. rufa and two to var. castanea. 



A fourth generation was produced by again pairing two specimens 

 of the var. rufa, and of fifteen specimens reared, two were typical of 

 the species and five referable to sub-varieties of castanea. 



A fifth generation, produced by again pairing two of the var. rufa, 

 gave the following result : — Sixteen eggs were reared, of which twelve 

 were typical of the species, two sub-varieties of rufa and two sub- 

 varieties of castanea. 



In a second experiment made with this species, two specimens of 

 the var. albolateralis were paired, and twenty-two of the progeny were 

 reared to maturity. All were typical forms excepting two which 

 were referable to the var. scharffi, of Cockerell. 



The results of these and other experiments all tend to point to the 

 following fact : — That the species Arion enipiricorum Fer. shows a 

 decided tendency to vary in four well-marked directions, viz., the 

 four varieties mentioned above, but that these are only colour varia- 

 tions and by no means constant. 



2. An'on subfuscus Drap. — As I have elsewhere^ pointed out, 

 the three principal varieties of this species are a red, a grey, and a 

 yellow form, and these three vary in a minor degree, giving rise to 

 colour variations which might well be classed under the variety. In 

 quite a large number of cases, where the young have been reared to 

 maturity, this tri-fold variation has been most marked, and where the 

 varieties have been bred from, the minor colour variations have 

 invariably been obtained. In confirmation of this, three somewhat 

 lengthy experiments may be detailed. 



Twenty-four eggs produced by the var. griseus CUge. with var. 

 succineus Bouill. gave the following results : — 

 10 typical A. subfusciis. 

 8 var. griseus. 

 4 var. succineus. 



2 in which the dorsum was yellowish-brown and the lateral 

 portion of the body grey. (Allied to vax.ferussaci Kalen.). 

 The two varieties were paired, but only five eggs were reared, all 

 of which were typical forms. 



Two subfuscus were next paired, and forty eggs were hatched and 



I Conc/wlogist, 1892, vol. i, p. 63. 



