178 Transactions.— Zoology. 
Hab. Mount Somers, Canterbury (Dr. von Haast), on limestone 
eliffs. 
Distinguished by its smooth shining surface and brown and white 
bands. Its generic position must remain doubtful until the dentition is 
known. 
PrEIFFERIA (?) orEssIDA, n.s. PI. ix., fig. x., and pl. xi., fig. n. 
Shell turbinate, depressed, thin, translucent, striated, umbilicus covered ; 
fulvous horny. Spire convex; whorls 51, slowly increasing, rounded, 
shining, finely irregularly striated or plaited: suture impressed: umbilicus 
very narrow, covered by the peristome: aperture slightly oblique, lunately 
rotund; peristome thin, regularly arched, the columellar margin slightly 
hind and reflected over the umbilicus. Greatest diameter ‘48, least 
:38; height :33 inch. ; 
Hab. Southland (G. M. Thomson). 
Jaw arcuate, flatly ribbed, the ribs indenting both margins. 
Dentition, 8385-1-35 ; varying from 82 to 87. Laterals about 17. 
Central tooth rectangular, twice as long as broad; the reflexed portion 
half the length of the base, slightly constricted on each side, and with a 
minute cutting point. Laterals with the reflexed portion bicuspid, the 
inher cusp carrying a cutting point which gets longer further from the — 
centre; outer cusp notched in the middle. Marginals broader than long 
with several cutting points; on the inner marginals the two points at the 
inner corner are larger than the others; the outer marginals are irregular 
and the points disappear altogether, 
In this species the shell is seen, under the microscope, to be finely 
obliquely reticulated, the crossing strie having diagonal directions. I 
formerly mistook it for H. guttula, but in that species the shell is described 
as very smooth, with an inconsiderable, sub-marginated suture, and the last 
whorl as callous beneath, in all which points it differs from our species. 
It is doubtfully referred to the genus Pfeifferia as the animal is not 
known. 
GERONTIA CORDELIA, N. " 
Shell sub-discoidal, PUN umbilieated, striated; colour pale horny, 
marbled with reddish brown and covered by a shining yellow epidermis. 
Spire convex ; whorls 41, slowly increasing, rounded, with tolerably regular, 
rather crowded, and rather coarse strie of old growth-lines; suture im- 
pressed; umbilieus broad, conical, showing all the whorls, but not gra- 
dated; aperture slightly oblique, sub-circular; peristome thin, right margin 
descending, columellar margin rapidly ascending but not vertical, the two 
margins not approaching. Greatest diameter :82, least +27; height :18 
inch, 
