SCHARFF: on a hybrid RUMINA DECOLLATA. 357 



specimens of the Algerian variety of the R. decollata^ which 

 is nearly as large again as the specimens I collected at A gen, 

 in the South of France. I then possessed a considerable 

 number from the latter locality, and put them together in one 

 large box, specially made for the purpose, and ascertained 

 the pairing of two varieties. 



" Some time after, the box was filled with hundreds of 

 young, of which I chose the strongest, and kept them in a 

 separate place. 



'' I watched them very attentively, and soon perceived 

 that they seemed to belong to the Algerian variety. like that, 

 the back of the animal was of a dark violet color, whilst the 

 foot had a slightly yellowish tint. 



" The shell was dark brown, bearing small longitudinal white 

 lines. 



" Nothing extraordinary manifested itself during the first 

 year ; most of them closed their aperture by means of an 

 epiphragm, and remained inert during the winter season. 



"In spring 1877, I remarked that the peristome of several 

 specimens grew like that of the original Algerian decollata. 

 The size of the shell was rather short, and the spire was com- 

 posed of only four whorls. In fact, they were like the French 

 specimens as regards size, only heavier and thicker. 



" The following year I was obliged to neglect my pupils 

 on account of various other occupations. However, as they were 

 in my room, I one day opened the boxes to see whether they were 

 well provided for, when I perceived to my great astonishment, 

 a few of them with a continued peristome, possessing a dentiform 

 blade, which seemed to me quite abnormal. 



" I have in my collection R. decollata from various parts 

 of France, Italy and Algiers, and I have only seen one individual 

 where I have been able to see a commencement of denticulation 



