328 Proceedings of the Royal Society of Edinburgh. [Sess. 
(cf. text-fig. A, p. 319). On the left side of the animal, in a position 
corresponding to that of the right penis, there is an equally well-developed 
penis, with a vas deferens, from which a seminal groove extends back- 
wards some distance, and finally disappears on reaching the dorsal surface 
of the body. There is no connection between the supplementary penis 
and the normal genital organs. 
LIST OF REFERENCES TO THE LITERATURE. 
Appellof, A., Teuthologische Beitrage, IV. “ Ueber einen Fall von doppel- 
seitiger Hektokotylisation bei Eledone cirrhosa (Lam.), D’Orb.,” in Bergens Museums 
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Babor, J. F., “ Uber den Cyclus der Geschlechtsentwicklung der Stylommato- 
phoren,” in Verh. Deutsch. Zool. Ges., Yers. iv. pp. 55-61, 10 figs. : 1894. 
Babor, J. F., Discussion on Simroth’s paper, “Uber Selbstbefruchtung bei 
Lungenschnecken,” in ibid., Yers. x. p. 147 : 1900. 
Bietrix — , “ Un cas de monstruosite de l’appareil genital cbez Y Helix 
pomatia ,” in Bull. Soc. Philomathigue Paris, Ser. 7, t. x. pp. 74-78 : 1886. 
Brock, J., “ Die Entwicklung des Geschlechtsapparates der stylommatopboren 
Pulmonaten nebst Bemerkungen liber die Anatomie und Entwicklung einiger 
anderer Organsysteme,” in Zeits. wiss. Zool., Bd. xliv. pp. 333-395, Taf. 22-25 : 
1886. 
Collinge, W. E., “On the Absence of the Male Reproductive Organs in Two 
Hermaphrodite Molluscs,” in Journ. Avat. Physiol., vol. xxvii. pp. 237-238: 1893. 
Collinge, W. E., “Notes on Slugs and Slug-like Molluscs,” in Journ. Mala- 
cology, vol. xi. pp. 14-15: 1904. 
Eisig, H., “ Beitrage zur Anatomie und Entwickelungsgeschiclite der Geschlechts- 
organe von Lymnaeus” in Zeits. wiss. Zool., Bd. xix. pp. 297-321, Taf. 25 : 1869. 
Giard, A., Fragments biologiques, 12. “Castration parasitaire probable chez 
les Ptero trachea,” in Bull. Sc. France Belg. (3), 1 Annee, pp. 309-310 : 1888. 
Jhering, H. von, “Ueber die Entwickelungsgeschiclite von Helix. Zugleich 
ein Beitrag zur vergleichenden Anatomie und Phylogenie der Pulmonaten,” in 
Jenaisch. Zeits. Naturw., Bd. ix. pp. 299-338, Taf. 17-18 : 1875. 
Jhering, H. von, “Zur Kenntniss der amerikanischen Limax Arten,” in 
Jahresb. d. malakozool. Ges., Bd. xii. pp. 201-218, Taf. 5 : 1885. 
Klotz, J., “Beitrag zur Entwicklungsgeschichte und Anatomie des Geschlechts- 
apparates von Lymnaeus ,” in Jenaisch. Zeits. Naturw., Bd. xxiii. pp. 1-40, Taf. 
1-2: 1889. 
Mangenot, C., “Un cas d’atr4sie de Torifice genital externe chez un Helix 
pomatia ,” in Bull. Soc. Zool. France., vol. viii. pp. 130-133, 1 fig. : 1883. 
Paravicini, G., “ Organi genitali anomali nell Helix pomatia” in Boll. Scient. 
Pavia, Anno xx. pp. 39-44, 1 Tav. : 1898. 
Peck, J. I., “ On the Anatomy and Histology of Cymbuliopsis calceola ,” in 
Studies Biol. Lab. Johns Hopkins Univ., Baltimore, vol. iv. pp. 335-353, Pis. 
36-39: 1887-1890. 
