290 PROCEEDINGS OP THE MALACOLOGICAL SOCIETY. 



diameter, being very thick and muscular. Behind its union with the 

 vas deferens it is continued as an equally thick and muscular 

 flagellum, about 1 mm. long, with a broadly rounded extremity. 

 The epiphallus and the unusually broad flagellum have a similar 

 histological structure. They are lined by a columnar epithelium, 

 which is folded so as to form minute papillse ; next to this there is 

 generally a little connective tissue, but most of the wall consists of 

 a thick outer layer of mixed longitudinal and circular muscle-fibres. 

 The penial retractor, muscle, as already mentioned, is attached to 

 the epiphallus towards its anterior end. The penis is nearly 2 mm. 

 long, and is considerably broader than the epiphallus, with a much 

 larger cavity, although its walls are somewhat flattened. It is smooth 

 internally, with a short broad penis-papilla projecting into its hinder 

 end and having the small opening of the epiphallus at its apex, 

 as shown in Fig. 6 on Plate VI. The penis, as well as the other genital 

 ducts, lies on the right side of the retractor of the right upper tentacle. 

 The genital atrium is rather small, but a few scattered gland-cells 

 are contained in its wall. * 



(2) The Affinities op Ochthefrila. 



In 1895 Pilsbry placed the genus Ochthephila or Geomitra next to 

 Helicella among the Siphonadeniate Helicidee, although he did so 

 with some doubt, and said : "it would obviously be quite idle to 

 discuss the origin or genesis of this genus until its anatomy is made 

 known." ^ Eecently Cockerell dissected a specimen of 0. pulvinata 

 (Lowe) from Porto Santo, and found that it had no dart-sac 

 or mucous glands ; he therefore suggested that the genus belonged 

 to the Epiphallogona, and that " Ochthephila represents a survival of 

 a type of Helicidae which is now mainly developed in the Oriental 

 and Australian regions ".^ He added, however, that he had found in 

 0. pulvinata a slender cylindrical organ closely resembling, on a 

 small scale, the supposed degenerate dart-sac of Theha cantiana, 

 and wrote : "If this structure is really a degenerate dart-sac, then 

 Ochthephila may be a member of the Belogona which, through 

 degeneration, simulates the Epiphallogona." 



It will be seen from my description and figures of the anatomy of 

 Ochthephila turricula (Lowe) that Cockerell's second suggestion is 

 undoubtedly the correct one, for this species possesses both a dart- 

 sac and mucous glands, though in a very degenerate condition. 

 Further, it appears that Pilsbry could not have done better than 

 place this genus next to Helicella, with which it seems to have close 

 affinities. 



Ochthephila turricula closely resembles Helicella and Theha (which 

 Pilsbry regarded as a subgenus of Helicella) in the external features 

 of the animal, in the form of the kidney, in the central nervous 

 system, in the retractor muscles, in the position of the penis on the 



' Man. Conch., ser. ii, vol. ix, p. 238. 

 * Journ. of Conch., vol. xvi, 1922, p. 311. 



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