Hovrrox,—On new Tertiary Shells. 819 
Length 13 inch. 
Locality. Petane. 
Aclis costellata, Pl. xviii., fig. 14. 
Shell minute, subulate. Whorls 6, rounded; the first two smooth and 
polished, the rest spirally grooved. Spire whorls with the two posterior 
spiral grooves deeper and broader than the others, and the rib between 
them raised higher; crossed by delicate longitudinal plications. Body 
whorl like those of the spire; the whole of the base very finely spirally 
grooved. Suture well marked. Aperture ovate, less than half the length 
of the shell; columella arched; umbilicus covered. 
Length, :18 inch. 
Locality. Wanganui. 
Odostomia sulcata. Pl. xviii., fig 15. 
Shell large, ovato-elongate, spirally grooved, the spire slightly gradated. 
Whorls 8, flattened; those of the spire with 5 to 7 narrow grooves crossed 
by longitudinal growth-lines; body whorl with 18 to 20 grooves, the anterior 
of which are sometimes closer than the posterior. Suture impressed. 
Aperture ovate, pointed behind ; columella with a single, posterior, oblique 
fold, almost or quite covering the umbilicus. 
Length, -62 to 1:0 inch ; breadth, °34 to *48 inch. 
Locality. Wanganui. 
The form of this shell is very variable; the length is from 2 to 23 times 
the breadth. 
Odostomia georgiana. Pl. xviii., fig 16. 
Shell rather elongated, shining. Whorls 10, flattened, polished, irregu- 
larly longitudinally marked, but without any spiral sculpture; body 
whorl very obtusely keeled. Suture impressed. Aperture oval, pointed 
behind; columella with a single deep, posterior, oblique fold, nearly or 
quite covering the umbilicus. 
Length, :58 inch ; breadth, +22 inch. 
Locality. Wanganui. 
Named after Mr 8. H. Drew's son, an indefatigable collector. 
Odostomia ( Parthenia) plicata. |. Pl. xviii., fig 17. 
Shell minute, ovato-elongated, longitudinally plicated. ^ Whorls 6, 
flattened, irregularly longitudinally, rather strongly, plicated on the posterior 
halfonly; the anterior half of the body whorl smooth; the whole shell 
faintly spirally striated. Suture impressed. Aperture ovate ; columella 
with a single, rather strong, fold; the umbilicus covered. 
Length, *12 inch. 
Locality. Wanganui and Petane, 
