Htjtton. — On Neiv Zealand Land Shells. 179 



Hab. Titirangi, Auckland (T. F. Cheesenian). 



I place this species in Gerontia from the general appearance of the shell, 

 but I do not know the animal nor the dentition. It differs from G. 

 pantherina in being more convex, in the epidermis not being plaited, in 

 being more coarsely striated,- in the right margin descending, in the 

 aperture being less oblique, and in its colours. 



Amphidoxa perdita, n. s. PL xi., figs, c and q. 



Shell thin, shining, pellucid, depressed, umbilicated ; colour pale olive 

 horny. Spire convex; whorls 3^-4, rapidly increasing, rounded, finely 

 irregularly striated ; suture deeply impressed ; umbilicus narrow, pervious ; 

 aperture oblique, lunately circular ; peristome thin, the right margin joined 

 closely to the next whorl. Greatest diameter -23, -least -2 ; height -18 

 inch. 



This shell differs from H. chiron in being higher, the umbilicus narrower, 

 and the right margin of the peristome not advancing. From H. novarce it 

 differs in being striated, in the suture being impressed and the spire convex. 

 From A', cornea it differs in being umbilicated. 



Animal with the mantle central, slightly reflected over the peristome of 

 the shell ; tail pointed, depressed, with a mucous gland. Colour dark 

 slate-grey, the mantle marbled with black and white ; sole of the foot dirty 

 yellowish. 



Jaw arcuated, narrow, not tapering, smooth, but with 30 or 40 delicate 

 rounded ribs. 



Dentition, 20-1-20. Laterals 6 or 7. 



Central tooth rectangular, longer than broad ; the reflexed portion 

 covering two-thirds of the base ; the sides concave, with a cutting point on 

 each ; the apical cutting point moderate. Laterals like the central ; but 

 the cutting points larger, and the outer margin of the reflexed portion more 

 excavated. Marginals quadrangular, broader than long, the inner with 

 three large cutting points ; the outer with a single broad dentated cutting 

 edge ; the last without any cutting edge. 



Hab. Grey mouth (E. Helms). 



Amphidoxa jacquenetta, n. s. PI. x., fig. c. 



Shell perforate, flattened, keeled ; colour pale brown. Spire flat, or 

 very slightly convex ; whorls 2± rapidly increasing, very slightly convex, 

 the last acutely keeled and rounded on the lower surface ; smooth, delicately 

 striated with growth-lines, the surface very finely and irregularly diagonally 

 reticulated, and crossed with faint distant spiral striae ; suture impressed ; 

 umbilicus very narrow ; aperture (?). Greatest diameter -2, least '12 ; 

 height -06 inch. 



