130 Transactions. —Zoology. 
ant that we should get acquainted with its dentition, and ] 
therefore give here the figures of the Jaw and part of radula, 
The jaw is composed of twenty-five separate strongly. 
papillate plaits. The radula has the formula 25—1—25; the 
central tooth is minute, unicuspid, the laterals and marginals 
bicuspid. For details in the dentition of this and the followin 
three species of Phriagnathus I refer to former publications 
by Professor Hutton and myself. 
16. Phrixgnathus pumilus, Hutton, sp. 1883. Plate XVII, 
figs. 20, 21. 
The jaw of this species was not seen by Professor Hutton 
when he examined the dentition. It is distinctly papillate, 
the plaits are narrow towards the ends, very broad in the 
middle; but this may differ with the individual. 
The central and lateral teeth are just as figured by Pro- 
fessor Hutton (Trans. N.Z. Inst., xvi., pl. ix., fig. Q). The 
marginals, which are figured here, are similar to the laterals, 
bicuspid, but shorter, quadrate. 
17. Phrixgnathus microreticulatus, Suter, sp. 1890. Plate 
XVII, figs. 22, 23. 
This species was described by the writer as Hyalina 
microret., but on examining the jaw and radula I saw that it 
belongs to Hutton’s Phrixgnathus. 
The jaw is formed of about eighteen separate slightly- 
papillate plaits; the radula has the formula 27—1—27, the 
rachidian tooth unicuspid, the laterals and marginals bicuspid, 
the last exceptionally tricuspid. 
18. Phrixgnathus allochroidus, var. lateumbilicatus, Suter, 
sp. 1890. Plate XVIIL., figs. 24, 25. 
This is another of my supposed Hyaline, which on 
examining the dentition turned out to be a Phrixgnathus ; 
jaw with about twenty-one separate papillate plaits ; formula 
of radula 14—1—14; central tooth tricuspid, with a median 
cutting-point, laterals and marginals bicuspid. 
19. Ariophanta* novare, Pfeiffer, sp. 1862. Plate XVIIL., 
figs. 26, 27. 
As mentioned in my list of the introduced land and fresh- 
water mollusca of New Zealand (Trans. N.Z. Inst., vol. XXIV., 
p. 280), I suspected Mr. Musson’s Zonitoides nitida, Miller, 
trom Lake St. John, Auckland, to be not this species, but 
Pfeiffer’s Hyalina novare. At my request Mr. Musson kindly 
sent me a number of shells and animals. I at once saw that 
ie ltr Male eae A Nive lth) oc, ce joy yim ddl, ply ee 
* Ariophanta, Des Moulins, 1829 (Nanina, Gray, 1834; not Risso, 1826). 
SES ee 
SE —_— 
be eS ee ee 
