318 LAND AND FRESHWATER 



the dart-sac, a simple sheath with the vas deferens given off at the 

 extreme end ; no doubt there is a retractor muscle here, but it was 

 not seen in tlio specimens I examined. In strong- transmitted 

 li<?ht it was noticed that the anterior end of the penis terminated 

 in a transparent point, of a diiJerent nature from the portion to 

 which it was attached (tig. 2 d). The spermatheea was not seen 

 complete either, and I could see no sign of the bifid duct at the 

 base. In one specimen it was very long (fig. 2 e), slightly swollen 

 and pointed at the end, and probably unites with the bulbous 

 mass near the generative aperture {sp.). 



My task of locating this species in its generic position in the 

 livalinia group of the Mollusca has been rendered comparatively 

 easy by the labour of Mr. John W. Taylor in his excellent * Mono- 

 graph of the Land and Freshwater Mollusca of the British Isles/ 

 Zonitoides, p. 133, and the photographic work of the late Mr. W. 

 Moss. Following Mr. Taylor's classification, Folita notahilis, in its 

 anatomy is similar to that of Zonitoides exccivatas. Bean, and 

 Z. nitidas. ^iliiller, particularly in the generative organs, which are 

 of a ty]ie quite unlike those of the more simple type seen in 

 N. alliaria, MiilL, nitidula, Drap., &c. ; the last-named species 

 Mr. Taylor places in the subgenus Folita, Held., created by that 

 naturalist in 1837. The form of the dart is absolutely the same as 

 ilxSit of Z. excavatus. I have noted a transparent termination of 

 the male organ (fig. 2 rZ, ^j.), and referring to figs. 184 & 185 of 

 p. 135 of the above Monograph, I am inclined to think it represents 

 the calcareous so-called penial plate there represented. 



The radula ])resents teeth of the same form as those shown on 

 p. 136, but the formula differs, thus : 



In excavatus it is 16.9.1.9.16 or 25 . 1 . 25 ; 



nitidus 20 . 5 . 1 . 5 . 20 or 25 . 1 . 25 ; 



notahilis 26 . 6 . 1 . 6 . 26 or 32 . 1 . 32. 



One example of the radnla of the last was mounted without 

 the loss of a single tooth in most of the rows. 



Conchologically notahilis is very distinct from excnvatus and 

 nitidvs; making an allowance for loss of colour in alcohol, there is 

 no sign of the brown so typical of most of the species of Hyalinia ; 

 in the grey or colourless species snch as pura and crystaUina, 

 the generative organs are not like those of Zonitoides. 



Great interest surrounds Z. notahilis as to whether it is an 

 indigenous species in Ceylon or introduced. If introduced, from 

 what part of the Northern Hemisphere did this Palaearctic genus 

 come? There is hardly any other part of this tropical region 

 to which species of the land mollusca might more easily be 

 carried than Ceylon, when one considers the thousands of acres 

 which have been brought under cultivation by European capital, 

 and that this was commenced so many years ago, long before tea 

 cultivation in India was started, which I can well remember was 

 about 1855. Managers and their assistants would be receiving 



