130 PROCEEDINGS OP THE MALACOLOGICAL SOCIETY. 



organs by making them homologous or analagous with the dart 

 sac apparatus of the Helices, and the glandular tissue which is present 

 in all of them is plainly called " dart gland ". For this assumption 

 I can see no sort of justification ; morphologically, in a group which 

 those who know more about the past than they do about the present 

 describe as of polyphyletic origin, it is at the best a dubious 

 speculation, functionally it is impossible. Apart, however, from 

 terminology, it forms the basis of a useful classification of the genus 

 into — 



(a) Without glands : 

 pellucida. 



(h) With glands : 



(a) Incorporated with the penis only, e.g. diapJiana. 

 (fS) Incorporated with the oviduct, e.g. major. 

 (7) Free, e.g. nivalis, hrevis, elongata, pyrenaica. 



The next thing to do is to extend our knowledge of the British 

 distribution of the species. It cannot, I think, be identified from the 

 shell, at any rate without much more experience. Any specimens 

 of Vitrina with relatively large dark bodies and rather flat-spired 

 shells should be examined anatomically ; the swelling on the oviduct 

 is easy to see on rough dissection, and any radula in which the outer 

 marginals have not got the multicuspid teeth of pellucida is very 

 suggestive. I should be glad of the opportunity of examining any 

 specimens ; they are most instructive if seen alive, failing which 

 they should be preserved in alcohol, not formalin ; dried bodies 

 are sufficient for the radula. 



Addendum. — -On 21st July, while we were collecting Acanthinula 

 lamellata in Mr. J. E. Cooper's locality at Burnham Beeches, Bucks, 

 Dr. E. J. Salisbury found another dark-bodied vivacious Vitrina, 

 which in genitalia and radula is identical with the Cusop snail, 

 except that the external glands on the oviducal mass are much 

 smaller ; the columellar lip is sharp. In my experience, full-grown 

 pellucida are unknown at this time of year, which may be another 

 difference between the two species. The locus here was a ditch 

 with beech and some holly leaves, the ground not calcareous ; A. 

 lamellata was the predominant species, and we found also Arion ater, 

 A. minimus, A. liortensis, A. circumscriptus, Hyalinia cellaria, H. 

 alliaria, H. pura, H. radiatula, Conidus fulvus, Pyramidula 

 rotundata, Punctum pygmacum, Acanthinula aculeata, Vertigo 

 edentula, and Acme lineata. 



