136 Transactions.—Zoology. 
margin shortly ascending, rather straight, and slightly reflected over the 
umbilicus : interior of the aperture strengthened with seven spiral plaits on 
the body-whorl, and another, rather distant, on the columella ; parietal wall 
with ten spiral plaits. Greatest diameter 0-08, least 0-07 ; height 0-05. 
Animal.—Body elongated, narrow ; eye-peduncles long and thick, ten- 
tacles moderate: mantle subcentral, rather anterior, enclosed: foot very 
long and narrow, with neither locomotive dise nor caudal gland. Colour 
pale grey, eye-peduncles and a stripe on each side of the head purplish ; 
foot pale brown. Dentition, 19—1—12. 
Hab. Greymouth (Mr. R. Helms). 
AMPHIDOXA CORNEA, Sp. nov. 
Shell thin, depressed, imperforate, striated, translucent; colour pale 
horny. Spire slightly convex; whorls 23, rapidly increasing, rounded, 
smooth, polished, finely striated with growth-lines; suture impressed : 
aperture very oblique, transversely oval; peristome thin, regularly arched, 
columellar lip slightly reflected. Greatest diameter 0:25, least 0-9. Denti- 
tion, 17-1-17. 
Hab. Auckland (Mr. T. F. Cheeseman). 
From A. compressivoluta this shell may be distinguished by the whorls . 
being convex instead of flattened ; from the other New Zealand species of 
Amphidoxa by being imperforate, and of a pale horny colour without mark- 
ings and without ribs. The mantle of the animal is marbled with black, 
which shows through the shell. 
AMPHIDOXA COSTULATA, Sp. nov. ; 
Shell small, subdiscoidal, umbilicated, shining but not polished, ribbed ; 
colour pale horny, longitudinally banded with reddish, the bands absent 
on the last half of the last whorl. Spire almost flat ; whorls 84, rapidly 
increasing, rounded, ornamented with fine spiral striatulations and close 
ribs, about 40 to 45 in the tenth of an inch, the interstices very finely 
reticulated ; suture impressed; umbilicus a narrow perforation at the 
bottom of a broad funnel-shaped depression, which is ribbed like the rest of 
the whorls; aperture oblique, transversely ovate ; peristome thin, regularly 
arched. Greatest diameter 0:14, least 0-1. Dentition, 14-1-14. 
Hab. Auckland (Mr. T. F. Cheeseman). 
This species is easily distinguished by the ribbing and spiral striatulations. 
Phrixgnathus, gen. nov. 
Animal heliciform. Mantle subcentral, protected by an external shell, 
over which it is reflected anteriorly. No locomotive disc to the foot. Foot 
rounded posteriorly and without caudal gland. Jaw papillate, imbricately 
folded. Teeth quadrate, the laterals bicuspid. Shell conical or turbinated, 
of five or six gradually increasing whorls ; peristome thin, straight. 
