120 PSEUDOPEAS. 



Subgenus EREMOPEAS Pilsbry. 



9. P. INTERIORIS (Tate). PL 25, figs. 17, 18. 



"Shell cylindrical, spire very long and tapering to an ob- 

 tuse apex; very thin, shining, greenish^white or pale yellow- 

 ish ; ornamented with slender, crowded, slightly arcuate axial 

 riblets, approximately as wide as the interspaces. "Whorls 

 nine, almost flat, but abruptly descending to the deeply im- 

 pressed suture. Aperture elongate-oval; peristome simple, 

 acute ; columellar margin nearly straight, thinly and narrowly 

 reflected, and almost concealing a minute umbilical fissure. 

 Length 10.5, diam. about 2.25 mm/ 7 (Tate). 



Central Australia: extending east and west from. Hart's 

 Eange to Stokes ' Pass, and north and south from the north 

 and outer flanks of McDonnell Range to Ilpilla Gorge (Tate). 



Stenogyra interioris TATE, Trans. Boy. Soc. South Aus- 

 tralia xviii, 1894, p. 191; Report Horn Exped. to Central 

 Australia, pi. 2, Zoology, p. 203, pi. 18, f. 14, 1896. 



With the exception of Pseudopeas tuckeri of the tropical 

 Queensland coast, this is the only Opeas-like snail of Australia. 

 Hedley has referred it to 0. gracile, but without, I think, 

 sufficient consideration. The shells I opened contained ob- 

 long embryonic shells of about 2y 2 whorls, arranged in a 

 single series like the eggs of Opeas. This acceleration is prob- 

 ably an adaptation to conditions of excessive aridity, unfav- 

 orable to the development of young from eggs. 



The sculpture of the protoconch (pi. 25, fig. 18) has not 

 been noticed hitherto. There are low weakly tuberculate 

 spiral threads, which cease at the conclusion of the nepionic 

 stage. My specimens were received from Professor Tate, and 

 are part of the original lot. 



10. P. TUCKERI (Pfeiffer) . PI. 22, figs. 7, 8 ; pi. 24, figs. 27, 28. 

 Shell perforate, cylindric-subulate, thin, longitudinally dis- 

 tinctly striate, rather glossy, waxen. Spire long, the apex 

 rather acute ; whorls 9, a little convex, the last scarcely one- 

 fourth the total length. Columella obliquely receding. Aper- 

 ture oval-oblong ; peristome simple, acute, the columellar mar- 



