448 MOLLUSCA FROM THE HOPE ISLANDS, N. QUEENSLAND, 



threads. Aperture subquadrate, plication strong, horizontal.- 

 Length 3-35; breadth 1*4 mm. 



A few specimens, from 5-10 fathoms, off the Hope Islands. 



Odostomia sperabilis, n.sp. 

 (Plate xli., fig.71.) 



Shell small, subcylindrical, imperforate, thin, subtranslucent, 

 smooth and glossy. Colour milk-white. Whorls five, plus a deeply 

 immersed heterostrophe apex, rather irregularly coiled, rounded, 

 with deep sutures. Sculpture: a few irregular!}^ disposed varices, 

 most frequent on the upper whorls, and faint, microscopic radial 

 striae. Columellar fold slight, margin of aperture a little thick- 

 ened. Length 3; breadth 1-1 mm. 



A few specimens, from 5-10 fathoms, off the Hope Islands; 

 also 15 fathoms, off the Palm Islands; and 17-20 fathoms, Mast 

 Head Island. 



This eccentric form perhaps belongs to the subgenus Oceanida 

 de Folin, which I know only by secondhand references. 



Odostomia tribulationis, n.sp. 

 (Plate xli., fig.72.) 



Shell small, solid, cylindro-conical, imperforate. Colour white. 

 Whorls four, and a half-sunken heterostrophe apex. Suture 

 deeply channelled. Sculpture : close straight perpendicular 

 radial riblets, about twenty-two to the last whorl, ceasing abruptly 

 at the periphery; their interstices are latticed by about half-a- 

 dozen weak spiral threads. On base, four equally spaced, smooth 

 spiral cords. Aperture ovate, columellar plication deeply enter- 

 ing. Length 1 65; breadth 0*8 mm. 



A i'ew specimens, from 5-10 fathoms, off the Hope Islands. 

 ryryulina lamyi Dautzenberg & Fischer,"^ appears to. differ by 

 fewer radials. 



* Dautzenberg & Fischer, Jouvn. de Conch, Hv. 1906, p. 19C, Pl.vL, f.15. 



