MURDOCH: ANATOMY OF SOMK NEW ZEALAND MOLLtTSCA. 171 



5. Pahyphanta Hochsietteki, Pfr. 



The muscular and nervous systems are similar to those of Rhytida, 

 as are also the pedal gland and cavity. Godwin-Austen has described 

 its anatomy (Proc. Malac. Soc. Lond., Vol. i, pp. 5-9, PL i), so that 

 further description seems hardly necessary. I may mention that the 

 oviduct and penis do not unite to form a common vestibule ; examined 

 externally, both are seen in the same epidermal pore, but eacli or«j;an 

 with a distinctly separate orifice, a space of rather more than a milli- 

 metre separating them. 



6. Xatalina Caffea, Per. 



A specimen has been dissected and compared with the several 

 species previously noted ; the example proves that the caecum or 

 appendicula of the oviduct forms a receptacle for the spermatophores. 

 The latter (PI. XVII, Fig. 11) is hard, almost leathery in substance, 

 curved and tapering towards the ends ; the anterior end is shortly 

 curved inward, hollowed out and scoop-like ; the outer surface is 

 longitudinally ribbed, and in cross-section seen to be deeply cleft into 

 segments. An accident deprived me of the foot before completing the 

 examination, and I am unable to state whether it has a pedal cavity 

 or not. 



Its anatomy is in many respects similar to that of Rhytida and of 

 Paryphanta ; nevertheless, it offers a marked generic distinction in the 

 peculiar type of its radula and the accessory organ on the oviduct. It 

 differs also in that the right tentacle retractor passes to the left of the 

 genital system ; but it remains to be proved whether this position is 

 constant in other species, and the same remark applies to Paryphanta. 

 In shell character it appears more nearly allied with Rhytida. 



COMPARISON OF THE FOREGOING GENERA. 



Rhytida and Paryphanta differ chiefly in the composition of the 

 shell and shape of the foot ; the former has a somewhat narrow foot 

 and acutely pointed tail ; in the latter the foot is expanded and the tail 

 ovate. In Paryphanta the shell is clothed with a thick periostracum, 

 and in certain species the apical whorls alone contain calcareous matter, 

 the remainder consisting of conchin (Suter, Journ. Alalac, vol. vii, 

 1899, pp. 49, 50). In Rhytida the shell contains more carbonate 

 of lime, and is more brittle. The radula does not present a very 

 decidedly marked difference. 



Rhenea comprises two species differing much in the character of 

 their shells : R. Coresia, Gray, in form and composition of shell is 

 a miniature Paryphanta Buslyi, Gray, whereas Rhenea Jeffreysiana, 

 Pfr., closely resembles a Flammulina. The latter appears to be a rare 

 species, and I have not had an opportunity of examining its anatomy. 

 Hutton has described the dentition (Trans. New Zeal. Inst., vol. xvi, 

 p. 1 72, pi. xi, rig. F), which in many respects resembles that of R. Coresia. 

 Whether both species are ovoviviparous, yet remains to be determined. 

 The narrow foot is more in accord with Rhytida, to which perhaps it 



