234 HUGH WATSON. 



other members of the Trig'onochlaminas, which Simroth 

 has shown to have probably been derived from the Par ma - 

 cellinte. This view is confirmed by the geographical 

 distribution of the genera. 



We may now consider the carnivorous genera which still 

 retain an external shell, for it seems certain that the shell of 

 Apera was originally external. 



The New Zealand genus Schizog'lossa resembles Apera 

 in mam^ ways, but it differs in its reproductive system, for in 

 Schizoglossa the male organs are much reduced, and there 

 is no receptaculum seminis.^ These features alone render it 

 improbable that Apera has been derived from Schizo- 

 glossa. According to Murdoch - the reproductive organs of 

 Paryphanta busbyi {Gray) bear a considerable resem- 

 blance to those of Schizoglossa, and 1 think that there can 

 be little doubt that the latter genus has been evolved in New 

 Zealand from that section of the Rhytidida3 to which 

 Paryphanta busbyi belongs. 



Strebelia possesses a receptaculum semiuis, but in this 

 genus the penial retractor is attached to the vas deferens 

 instead of to the penis itself. And, judging from Strebel's 

 figures, the salivary glands iire united below the crop, and 

 not above it as in Apera.^ Moreover, it does not seem likely 

 that a purely South African genus should have been evolved 

 from a slug which is only found in Mexico. 



There remain the European carnivorous slugs, Da u de- 

 li ardia and Testacella. Of these Daudebardia differs 

 widely from Apera in its pedal gland, nervous system, 

 reproductive organs, excretory system, etc. There can be no 

 doubt that Apera has not been evolved from Daudebardia. 

 On the other hand, Testacella has man}'^ points in common 



• Hedley, C, 'Proc. Linn. Soc. N.S.W.' (■2nd ser.), 1893, vol. vii, 

 p. 390, pi. ix, fig. 4, pi. X, fig. 9; Collinge, W. E., 'Ann. Mag. Nat. 

 Hist.' (7tli ser.), 1901, vol. vii, p. 72, pi. ii, fig. 30. 



2 ' Trans. N. Z. Inst.,' 1903, vol. xxxv, pp. 260. 261, pi. xxvii, figs. 4. 5. 



' ' Beitrag. z. Kenntn. d. Fauna Mexikan. L.-u. Silsswasser-Conchy- 

 lien,' 1878. vol. ill, pis. i. ii. 



