MURDOCH: ANATOMY OF SOME NEW ZEALAND MOLLESCA. 1 P>9 



when preparing the animal for dissection. The buccal mass (PI. XVII, 

 Fig'. 3) is large and cylindrical, the posterior end curved down and 

 forward ; the salivary gland (s.g.) dark in colour, is composed of 

 two lobes, but the cohesion of the two is so intimate that it may be 

 considered a single median gland, with two ducts (s.d.) emptying into 

 the buccal cavity. The dentition (PL XVII, Fig. 2) has the formula 

 9:0:9; the teeth, disposed in numerous transverse rows which form 

 an obtuse angle, are all aculeate, robust, aud smooth, the second one 

 being the largest, from this outward gradually getting smaller; the 

 third equals the second in length, but less robust ; the first about 

 equals the fifth. The absence of a central tooth leaves a wide 

 rhachidian cleft. The above description is slightly at variance with 

 that published by Captain Hutton (Trans. Xew Zeal. Inst., vol. xvi, 

 p. 172, pi. xi, fig. E). 



Genitalia (PI. XVII, Pig. 4) simple : penis (p.) with the retractor 

 muscle (r.inp) at the posterior end, the vas-deferens (v.d.) enters 

 a little below the apex, and forms a short slender tube. The spermatheca 

 (spr.) is small and pear-shaped, resting on a short narrow neck; it is 

 situate at the posterior end of the free tube of the oviduct (ovd.), and 

 partly concealed by the adjoining sacculated portion. The right 

 tentacle retractor passes on the left of the genital system. The 

 pedal gland forms a minute tube ; doubtless, the tunnel-like cavity in 

 the tail occurs also, but, unfortunately, it was not investigated when 

 dissecting the animal, and want of material prevents the question 

 being settled for the present. 



The nervous system, in its structure and position, is so similar to 

 that of Rhjtida that a description seems unnecessary. 



4. SCHIZOGLOSSA XoVOSEELANDICA, Pfl\ PI. XVII, Figs. 8-10. 



The animal has been excellently described by Hedley (Proc. Linn. 

 Soc. Xew South Wales, ser. n, vol. vii, pp. 387-392, pis. ix, x), 

 and the alimentary and genital systems fully treated. There is little 

 to add to the description of the external features, except to note the 

 presence of two small labial tentacles. The mantle (PL XVII, Fig. 9) 

 lias an even margin, with two small lappets on the under side; the 

 right (r.l.) proceeds forward from a little behind the respiratory pore 

 (rs.p.), extends to almost a third of the length of the mantle margin, 

 and forms a narrow fold ; the left (l.l.) is minute, simply a rudiment, 

 and in some specimens difficult to detect. 



The points of attachment of the principal retractor muscles are of 

 special interest. Hedley pointed out the remarkable little pit, 

 excavated in the shell, for the reception of the shell, or columellar, 

 muscle, and the writer noted a small elongated muscle-scar on the 

 left side of the shell (Proc. Malac. Soc. Lond", Vol. i, p. 138). Fig. 8 

 of PI XVII shows the position of these muscle-scars, as well as 

 the thick callous rib, which iu this example borders the scar on the 

 columella. 



Dissection of the animal (PL XVII, Fig. 10) reveals the following 

 features : — The buccal mass retractor (b.m.r.) is inserted in the 



