MURDOCH : ANATOMY OF SOME NEW ZEALAND MOLT.USOA . 167 



unites with the buccal mass in the form of a hollow cone, applied to all 

 sides of the posterior end. The oesophagus opens into the buccal cavity 

 in the anterior third of the mass, and so do the two salivary ducts ; 

 the salivary glands partly envelop the oesophagus, the inner edges of 

 each gland are pressed together, giving the appearance of a single 

 median gland, they are readily separated, and each seems functionally 

 distinct. The other portion of the alimentary canal closely resembles 

 that of Helix. The dentition has been described and figured by 

 Hutton (Trans. New Zeal. Inst., vol. xvi, p. 167, pi. x, fig. P) ; 

 Moss, too, gives a good figure of the teeth of a half-grown specimen, 

 possessing a central tooth, and describes a radula having an abnormal 

 formula (Trans. Manchester Micro. Soc, 1894, pi. ii, fig. 3). An 

 examination of the teeth of four specimens gave the following result : 

 two fully adult, 11:1:11, the outermost tooth missing; two young 

 examples (diam. of shells 7 mm.), 12 : 1 : 12; the teeth increase in size 

 from the centre to the tenth, which is the largest, the eleventh 

 much smaller, and the last minute. In the adult specimens, I find 

 here and there a central tooth scarcely more developed than the 

 corresponding tooth in the young; the ten laterals on each side much 

 exceed those of the young in size; but in the eleventh tooth there is 

 no difference in size, the young one equals the adult ; the growth 

 of this tooth is arrested during the early life of the animal, and, 

 like its outer neighbour, when present, has become functionless. To 

 some extent this applies to the central tooth, and may account for its 

 loss in some specimens. 



The pedal gland opens below the mouth ; it extends back in the 

 body-cavity as a simple tube, with one or two small convolutions near 

 the posterior end, and terminates in the substance of the foot. A small 

 tunnel-like cavity extends from the point where the gland ends to 

 almost the end of the tail; it does not open at the posterior end in 

 a mucous pore ; from the sides of this cavity proceed numerous small 

 ducts ; these are again divided, and extend to almost every part of the 

 foot, supplying it with mucous. 



Genitalia (IT. XV11, Fig. 6). — Penis (7;.) with the retractor 

 muscle (r.m.p.) at the apex; the prolongation, or epiphallus, («//«.) 

 arises from the posterior third ; between this point and the insertion 

 of the retractor muscle, the penis appears folded upon itself, and the 

 two parts welded together ; the duct of the epiphallus enters 

 the penis cavity at the apex, and the interior walls of both are studded 

 with minute papillae. An examination of several specimens proves 

 a small amount of variation in the male organs, but none whatever 

 on the female side (Pigs. 6a and 6b are given in illustration of this). 

 The epiphallus usually rests on the dorsal surface of the buccal mass, 

 except when it takes the form shown in Pig. 6b. The ovotestis small 

 and imbedded in the liver, hermaphrodite duct (h.d.) closely convoluted, 

 albumen gland (al.g.) large. The spermatheca (spr.) sub- cylindrical 

 in its lower portion, thence a somewhat contracted and twisted upon 

 itself, slightly enlarging above and closely adhering to the uterus. 



The muscular arrangement is very simple: the tentacle and buccal 

 mass retractors arise from the columella! muscle ; the former, at about 



VOL. IV.— MARCH, 1901. 12 



