HORN EXPEDITION—MOLLUSCA. 
203 
The species-name is in compliment to my colleague, to whose assistance the 
rich gathering of specimens of this species is largely clue, and to whoso co-operation 
in other field-work I now tender my grateful acknowledgments. 
Family Stenogykida:. 
Stenogyra intepiopis, Tate. (Plate XVIIL, Fig. 14.) 
llefercnce—Trans. Roy. 8oc. 8. Aust., vol. xviii., p. 191, 1894. 
Shell cylindrical, spire very long and tapering to an obtuse apex ; very thin, 
shining, greenish-white oi‘ pale yellowish; ornamented with slender, crowded, 
slightly arcuate axial rililets, approximately as wide as the interspaces. Whorls 
nine, almost Hat, hut abruptly descending to the deeply impressed suture. 
Aperture elongate-oval; peristome simple acute; coluniellar margin nearly 
straight, thinly and narrowly reflected, and almost concealing a minute undjilical 
fissure. 
Dimensions. —Length,TO-5 ; width, about 2-25. 
Localities. —One of the commonest snails of the Larapintine region, extending 
east and west from Hart’s Range to Stokes’ Pass, and north and south from the 
north and outer Hanks of McDonnell Range to llpilla Gorge. 
Affinities. —The only species of the genus hitherto recorded for Australia is 
Bulinius tuckeri., Pfr., of which Cox, in his Mon. Austral. Land Shells, says, p. 70, 
that it “ varies considerably in size and slightly in acutqness of the spire, and also 
in the distinctness of the longitudinal strice.” 
Compared with numerous specimens of S. tuckeri taken by me at Port 
Darwin, S. interioris presents the following combination of characters, which show 
no perceptible variability, more slender form and narrower whorls. Thus in a 
length (if 10‘5 mm. S. interioris has nine whorls, S. tuckeri has eight, and the 
greatest width of the latter is near three as against 2‘25 ; moreover, the whorls are 
less convex, the suture profound, and the riblets finer, more regular, and closer 
together. 
Mr. Hedley suggests that if the C. Aust. shell be considered of specific rank it 
should be called A. novemgyrata., Mousson, J. de Conch., vol. 1876, p. 126, 1870. 
Unfortunately that particular volume is not accessible. Rut in view of the isola¬ 
tion of A. interioris in contiast to the coastal habitat of A. gracilis and its varieties, 
there is every probability a careful comparison of actual specimens will justify the 
retention of the Central Australian shell as a distinctive species. 
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