546 ScHAKFF — On the SluffS of Irelayid. 



brown powder, so as to produce a light brown tint (Plate LVI., fig. 20). Below the 

 lateral bands tlie body colour is a light brownish-gray. 



According to Siuu'oth (38) the light colour is produced by warmth, and the dark 

 by cold; but whether this explanation holds good in the case of the two varieties 

 of A. hortensis occurring in the same locality at the same time of year, seems to 

 me extremely doubtful. However, I shall refer to this again in the chapter on 

 colour. 



The largest specimens of this species were 35 mm. long. The mucus is yellow 

 and somewhat sticky. 



Anatomy (Plate LVIL, fig. 34). — As in the other species the characteristic part 

 of the anatomy is to be found in the lower portion of the reproductive organ. As 

 in A. ater there is an upper (wy.) as well as a lower vestibule (/i^.). The free 

 oviduct {ov.) is long and widened in its lower part. The sperm-duct [sp.) ends in 

 a somewhat swollen " Patronenstrecke " {pat.), whilst the long-stalked recep- 

 taculum {rec.) is round. The genital retractor muscle [nn.) divides into two 

 bundles, one going to the duct of the receptaculum, the other to the oviduct. 



The calcareous grains under the mantle are, in this species, often aggregated so 

 as to form a rudimentary shell, which, according to Lessona and Pollonera (21) iu 

 Italian specimens is well developed. 



Reproduction. — I kept about fifty specimens in captivity from the middle of 

 September to the end of October, but no deposition of ova took place, nor did I ever 

 see ova that I could refer to this species. Simroth (38) had some eggs deposited 

 by captive specimens, which were perfectly round and clear, with a diameter of 

 2 mm. 



It is remarkable that very young specimens of this species have a keeled back, 

 but this keel, not being different in colour from the surrounding wrinkles, is not 

 very easily seen — and it entirely disappears in half-grown specimens. 



It seems to me probable that the deposition of ova takes place in the early 

 months of summer or spring, but additional observation is needed also with regard 

 to the duration of life in this species. All the specimens I have seen during winter 

 were pretty large, mostly half-grown, which leads me to sup^Dose that no deposition 

 of ova takes place during autumn. 



Habitat. — Simroth (38) states that A. hortensis is a South European form, and 

 probably does not occur north of the 52" of latitude. However, he has since 

 examined the Irish forms, and pronounced them identical with the German ones, 

 so that we may safely conclude that it does extend considerably farther north than 

 Simroth anticipated. 



The same author states that he has never met with a specimen anywhere but 

 in gardens, churchyards, and within villages. 



In Ireland, although also very common in gardens, it certainly has a wider 



