E-ndodont ,.} GASTROPODA. 685 



3. Shell pupiiorru, cylindrical, aperture toothless . . . . PHENACHAROPA. 



4. Shell elevated, dome-shaped, altitude about equal to the 



diameter, aperture toothless . . . . . . ^EscHBODOMUS. 



5. Shell depressed, subdiscoidal, periphery convex or sub- 



angular, surface rib-striate, openly unibilicated, aper- 

 ture toothless .. .. .. .. .. CHAROPA. 



Subgen. 1. THAUMATODON, Pilsbry, 1893. 



Thaumatodon, Pilsbry, Mau. Conch. (2), ix, 26. Type : Endodonta multi- 

 liini'lltiiti, Garrett. Pitys, Pease, P.Z.S., 1871, 450 (in part) ; Garrett, 

 Journ. Acad. Nat. Sri. Philad., viii, 1881, 388 ; not Pitys. Beck, Ind. 

 Moll., 1837, 9. 



Shell discoidal, the spire low. convex ; umbilicus open or closed ; 

 periphery generally broadly rounded ; surface rib-striate, unicoloured 

 or flammulate ; aperture having internal teeth or folds upon the outer 

 wall and the parietal wall, sometimes lacking upon the latter. 



Distribution. Polynesia, Philippine Islands. Celebes. New Zealand, 

 New Caledonia, Tasmania. 



I'i'iiHirk*. The genus Ajrodonta, Melvill and Ponsonby, A.M.N.H. 

 (8), i, 1908. 133, from Natal, seems to be very nearly allied to T-han- 

 iiHit.otJon and P/ //''>, X/DII. 



KEY TO SPECIES. 



1. Aperture with 1 lamella on the parietal wall, at about the 



middle ; lamella strong . . . . . . . . vari<-<.i*<i. 



2. Aperture with 2 lamellae on the outer wall . . . . . . cryptobidens. 



3. Aperture with 1 lamella on the parietal and 2 on the outer wall . . tau. 



4. Aperture with 2 lamellae on the parietal and 4 on the outer wall Jessica. 



6. Aperture with 1 lamella on the upper part of the parietal wall; 



lamella long, slender, low . . . . . . . . monopln.'-. 



1 Endodonta cryptobidens, Suter, 1891. Plate 9, fig. 14. a. b. 



Pitys cryptobidens, Sut., T.N.Z.I., xxiii, 1890 (1891), 89, pi. 17, f. 7, a-c, M, X. 

 Patnln (Endodonta,} cri/ptobidens, Sut. : Pilsbry, Man. Conch. (2), viii, 

 85. pi. 24, f. 28-31. Endodonln cryptobidens, Sut. : Hedley and Suter, 

 P.L.S. N.S.W. (2), vii, 651. E. (Thaumatodon) cryptobidens. Sut., J. de 

 Conch., xli, 258. 



Shell minute, discoidal, unibilicated, greyish, not shining, very 

 fragile, subtransparent, minutely costate. Sculpture consisting of very 

 fine and extremely close-set radial riblets, about 40 per millimetre, 

 slightly bent forwards, but almost straight on the upper surface, 

 sinuated at the periphery, and straight on the base ; interstices 

 minutely reticulated ; protoconch microscopically strongly spirally 

 striate. Colour cinereous. Spire, flat. Protoconch of If convex 

 whorls. Whorls 4|, narrow, convex, regularly increasing, the last 

 not descending. Suture deep. Aperture rotundly lunate, subvertical. 

 slightly excavated by the penultimate whorl. Peristome simple, acute, 

 somewhat flattened at the base, the upper margin advancing ; interior 

 with 2 teeth, one on the basal margin, rising from a small callosity, 

 the second near the middle of the outer wall : both teeth are some 



