WOTTON : LIFE-HISTORY OF ARION ATER. 159 



microscopical differences in colour mutations, seemingly for the 

 purpose of appending their names to hair-splitting varieties, or 

 in hunting up obsolete names, with the apparent object of 

 making sweeping changes in the present nomenclature — which 

 can only cause endless confusion — would not be more profitably 

 spent in studying the habits and structure of some of our less- 

 known molluscs? 



On the first day of August, 1889, I obtained two fine speci- 

 mens of Arioii ater whilst on a collecting expedition. The 

 colour of one was a uniform dark-reddish brown, the other 

 uniform light yellow ; both having the deep-orange fringe round 

 the foot characteristic of the variety rufa. I had a box made 

 for their reception, which had a teak-wood bottom, glass sides 

 and ends, and a tightly-fitting, portable, perforated zinc top. 

 It was of the following dimensions : — 15 inches long, 8 inches 

 wide, and 7 inches deep. The bottom was covered with turf, 

 about 2 inches deep, on which was placed two or three lime- 

 stones, and also a pot containing water. The turf was renewed 

 weekly and the water daily. On the fifth of August the two 

 Arions took possession of their new abode, where they seemed 

 as happy and contented as slugs could well be. On the tenth 

 of the following month I detected them in the act of conjuga- 

 tion, the connection lasting about twenty-five minutes. From 

 this time until the eggs were deposited, the animals assumed 

 rather a sickly appearance, the colours waxed duller, and the 

 bodies got somewhat dry, apparently on account of a scarcity 

 of slime. 



The dates on which the batches of eggs were deposited 

 and the number in each batch were as follows : — 



The Light-Yellow Avion. The Reddish-Brown Arion. 



