WATSON : DEFICIENCIES IN THE VERTIGININ^. 275 



LehmarLn's observations on these very minute species may not be 

 altogether accurate. 



Columella edentula (Drap.). 

 (=: Sphyradium edentulum (Drap.) of many authors.) 



Four specimens collected by Dr. Boycott at Cothill, Berkshire, in 

 November, 1921, and two additional examples found in the same 

 locality in June, 1923.^ — All the specimens have male organs, which 

 consist of a comparatively small penis, without any apparent 

 glandular tissue, and a vas deferens of moderate length, which enters 

 the penis at its extremity. The male organs thus agree with Hanna's 

 description of American specimens,^ rather than with the account of 

 Lehmann, who describes and figures two penial appendices in this 

 species.* 



The hermaphrodite gland appears to form a single cluster of 

 follicles. The hermaphrodite duct is darkly pigmented, and is 

 swollen near the albumen gland to serve as vesicula seminalis. 

 An extremely small prostate gland seems to be present on the inner 

 side of the posterior end of the spermoviduct, that is to say, in the 

 usual position of the prostate in the Pupillidse. The spermoviduct 

 and the glandular oviduct in front of it are both rather large, and of 

 the same general character as in Vertigo antivertigo and F. suhstriata ; ^ 

 but where they join there is a part having a slightly different histo- 

 logical structure, which may possibly correspond to the more distinct 

 middle portion of the glandular genital duct of the last species. The 

 non-glandular part of the oviduct is short ; the vagina is longer, but 

 the genital atrium is very short. The receptaculum seminis is 

 situated near the junction of the spermoviduct and the glandular 

 oviduct, i.e. about half-way up the glandular part of the genital 

 duct, and is nearer the inner than the outer side. The receptacular 

 duct is therefore of moderate length. 



These specimens differ from Hanna's description in that the 

 hermaphrodite duct is slightly convoluted towards its anterior end, 

 the glandular wall of the spermoviduct is folded internally, and the 

 genital atrium, though very short, is not entirely absent. These 

 apparent differences, however, may be chiefly due to differences in the 

 methods of observation ; they need not be held to prove that the 

 form examined by Hanna is specifically distinct from that found in 

 England, especially as Sterki has stated that " the American form 

 is absolutely identical with the palaearctic ".* 



The Presence and Absence op Male Organs in these Specimens. 



The following table summarizes the facts respecting the presence 

 and absence of male organs in the specimens described above : — 



1 These two specimens were not cut into sections like the others, but I 

 examined their male organs by ordinary dissection. 



2 Proc. U.S. Nat. Mus., vol. xli, 1912, p. 375. 



3 Op. cit., p. 143, pi. xiv, fig. 49. 

 * Nautilus, vol. x, 1896, p. 76. 



