SOME NOTES ON THE SO GALLED APPENDIX OF 

 HELIOELLA BARBARA (1). 



By II. OVERTOX. 



Some short time ago I communicated to the Midhuid Malacological 

 Society, a paper dealing with various points in the anatomy of Helicella 

 barbara {Jj.)= Helix acuta. 



There are many points of interest, and they have formed the subject 

 of various papers by different writers. Thus Schmidt, in 1854 '^', 

 described a small calcareous organ at the base of the penis ; Fischer, in 

 1856 '^', described and figured the spermatophore ; Ashford, in 1885 '■'" 

 gave a figure of the generative organs ; as also Moss and Paulden, in 

 1892 '^', the latter authors giving a short description. 



With reference to the calcareous organ described by Schmidt, I am 

 of opinion that this is a provision to assist in holding the organs 

 together during copulation, so as to ensure the transference of the 

 spermatozoa. As can easily be seen in dissection, the true penis is very 

 short. 



There is no true dart-gland in this mollusc, but a small, glandular 

 diverticulum, which has been very differently interpreted by various 

 authors. Moquin-Tandon termed it a simple mucous gland, which, as 

 pointed out by Ashford, can scarcely be correct. Moss and Paulden 

 refer to this organ as a gland of doubtful function ; while Mr. J. W. 

 Taylor '®' describes it as an appendix, and regards it as probable that 

 its affinities are with the semi-independent fiagellum in Bithynia, 

 Buliminus, etc. 



While this organ cannot be regarded as a simple mucous gland, it 

 certainly is not, in my opinion, homologous with the flagellum of 

 Bithynia, etc. 



The gland in cjuestion opens into the vestibule on the left-hand 

 side, close to the opening of the short vagina. It is 4*5 millim. in length, 

 with a maximum diameter of "5 millim. and a minimum diameter of 

 •2 millim., and lies coiled upon the vestibule and vagina. Near to the 

 distal end of this organ there is a small muscle, which attaches it to the 

 common duct, opposite and just above the point where the vas deferens 

 is given ofi (Fig. 1). 



1. Geschlechtsapparaf, der St.vlommatophoren. 



2. Journ. de Conchyl., 1S56. " 



3. Journ, Contli., 1885, vol. iv, p. 270. 



4. Trans. Manchester Micros. Sec, 1892, pp. 1-5, pi. 



5. Monog. L. & F. Moll., 1900, vol. i, p. 363. 



