74 HELIX-CALYMNA. 



the interstices very finely reticulated ; suture impressed ; umbilicus 

 a narrow perforation at the bottom of a broad fuunel-shaped depres- 

 sion, which is ribbed like the rest of the whorls; aperture oblique, 

 transversely ovate ; peristome thin, regularly arched. Greatest 

 diameter 0'14, least O'l. Dentition 14-1-14. (Hutt.*) 



Province of Auckland, New Zealand. 



Amphidoxa cosiulata HUTTON, Trans. N. Z. Inst. 1882, p. 136; L 

 c., 1883, p. 171, t. 10, f. A (dentition). A. (Calymna} costulata 

 HUTTON, L c., 1883, p. 199. Calymna costulata SUTER, L c., 1891, 

 p. 277. 



Distinguished by its ribbing and spiral striation. The figures 

 were drawn by Mr. Suter from Prof. Button's type. 



G. LAVINIA Hutton. Unfigured. 



Shell subdiscoidal, umbilicated, ribbed ; color yellow-horny, mot- 

 tled with rufous on the upper side. Spire flat ; periphery rounded ; 

 suture scarcely impressed ; whorls 3i, rapidly increasing, rather 

 flattened above, rounded below ; upper surface not shining, evenly 

 and closely ribbed, ribs about 18 in the tenth of an inch ; lower 

 surface smooth, shining, longitudinally striated and irregularly 

 spirally striatulated ; umbilicus moderate, showing all the whorls ; 

 aperture oblique, rotundly lunar ; peristome thin, the margins 

 approaching; columellar margin not reflected. 



Greatest diameter '5, least '4, height '25 inch. (Hutt.') 



Palmerston ; Wellington, N. Z. 



A. lavinia HUTTON, Trans. N. Z. Inst. 188:], p . 180, 199. 



Umbilicus wider than in A. costulata, and ribbing coarser, besides 

 being much larger. 



G. FEREDAYI Suter. PL 22, figs. 58, 59, 60. 



Shell small, globosely depressed, imperforate, shining, pale-horny, 

 without markings, thin, transparent ; with fine ribs, arcuated on the 

 surface and disappearing beneath, about 25 to 30 in the tenth of an 

 inch (10-12 per mm.). Spire short, obtuse. Whorls 3}, rapidly 

 increasing, rounded. Suture impressed. Aperture oblique, rotundly 

 ovate. Peristome thin, straight, regularly arched, the upper part 

 advancing. Columellar margin somewhat bent to the left, not 

 reflexed. Margins approximating. Umbilical region infundibuli- 

 form, imperforate. Diameter O'l 4 in. (3'5 mm.), height O'OS in. 



(2 mm.). (Suter.') 



Hastwell, Forty-mile JBush, North Island, N. Z. 



