SITTER : ON NEW NoN-MARINE SHELLS FROM NEW ZEALAND. 239 



carinae on the base, the upper one arising from the junction of the 

 outer lip with the whorl and terminating a little below the middle of 

 the outer lip ; the lower rib departs from the middle of the body- 

 whorl between the margins of the mouth, and ends at the distal side 

 of the basal lip ; no microscopic spiral striation is present. Colour 

 fulvous to brown. Epidermis thin, slightly shining ; there may be 

 axial membranous plaits, but in the only specimen before me they 

 have evidently been lost. Spire conical, of the same height as the 

 aperture ; a])ex obtuse. Protoconch consisting of one whorl, which is 

 globular and smooth. Suture deeply impressed. Aperture circular, 

 peristome slightly reflexed and callous, but sharp ; notch at the suture 

 very indistinct ; columella concave, partly concealing the umbilicus, 

 which is deep and of about -5 millim. diameter ; the umbilical tract 

 immersed and margined by the lower carina. Operculum thin, circular, 

 multispiral, with membranous outer and central processes. Alt. 5, 

 diam. 4-5 mm. 



Hob. — Kamo, near Whangarei (Mr. C. Cooper). 



This is a very well characterized species, easily separated from all 

 our other species of the genus. Type in my collection. 



8. DiPLODON Menziesi, Gray, n.subsp, acdta. PI. XXII, Figs. 11, 12. 



Distinguished from the species by the very distinctly rostrate 

 posterior end, the nearly total absence of radial sculpture, and by 

 being more compressed. Only young shells show traces of radially 

 arranged nodules near the beaks. The basal margin is generally more 

 straight than in typical D. Menziesi. The beaks are much corroded 

 in all the specimens I have. The shell is rather thin, yellowish-brown, 

 with strong concentric sculpture, approaching D. rugaia, Hutton. 

 The interior is nacreous olive, the hinge not different from that of the 

 species. Alt. 40, long. 7(), diam. 16 mm. 



Hab. — Lake Omapere, between Bay of Islands and Hokianga. The 

 shells were collected by Miss Willis, of Ohaeawai, and kindly given 

 to me by Archdeacon P. Walsh, of Waimate. To both of them my 

 best thanks are due. 



The outline of this subspecies is very nearly that of D. depauperata, 

 Hutton, but the hinge is very different ; it also has almost exactly the 

 outline of Anodonta complanata, Ziegler, of Europe. Type in my 

 collection. 



Appendix. 



Mr. Charles Cooper, of Auckland, submitted to my examination the 

 land and fresh- water shells collected during a trip round the North 

 Cape in the Government steamer " Hinemoa " in 1905, and the 

 following table gives the geographical distribution of the various 

 species obtained. Localities: 1, Little Barrier Island; 2, Poor 

 Knights Islands; 3, Whangaroa Harbour; 4, Tom Bowlines Bay, 

 east of North Cape ; 5, Cape Camel, "west of North Cape ; 6, Te 

 Reinga; 7, Kamo. 



