880 Transactions, —Geology. 
Scalaria marginata. 
Shell large, elongated, imperforate.  Whorls (?), flattened, distantly 
longitudinally ribbed, 8 in a whorl, sub-equal, the interstices smooth or 
very delicately spirally lined; the whorls sharply keeled at the base, the 
keel shows in the spire TEEN just above the suture ; the longitudinal ribs 
end at the spiral keel; base of the body whorl concave, smooth. Aper- 
ture (?). 
Length, (?); breadth, *7 inch. 
Locality. Curiosity Shop. 
A fragment only of this very well-marked species is in the Canterbury 
Museum. 
Trochus nodosus. 
Shell small, conical, imperforate, the spire acute. Whorls 6-7, flattened, 
keeled, below the keel bent parallel to the axis; keel placed a little above 
the suture and with a single row of tubercles, about 9 on a whorl. Body 
whorl bent vertically below the keel for a short distance and then flattened, 
giving a double keel to the body whorl, the lower of which is smooth ; base 
spirally striated; apparently no umbilical callus. Aperture rhomboidal. 
The whole surface of the shells appears to be finely cancellated with spiral 
and longitudinal lines. 
Length, ‘54 inch ; breadth, :45 inch. 
Locality. White Rock River. 
Corbula humerosa. 
Shell small ovato-trigonal, much inflated, smooth, with irregular growth 
lines; sub-equilateral, slightly produced and rounded posteriorly, not cari- 
nated, 
Length, :25 inch; height, -18 inch. 
Locality. White Rock River. 
Corbula pumila. 
Shell small, ovate, concentrically suleated; sub-equilateral, slightly 
produced and truncated eRe ; slightly angled. 
Length, :8 inch; height, -2 
Locality. White Rock t gn ; 
Differs from C. erythrodon in being shorter and less angled behind. 
From C. sulcata it differs in being larger, more compressed, and in the sulci 
being smaller and more numerous. 
Pholadomya neozelanica. 
Shell oblong, very inequilateral, moderately ventricose, the posterior end 
compressed. Concentrically ridged, about 12 to an inch; the ridges rounded, 
broader than the grooves. Central portion radiately ribbed, ribs moniliform, 
not so strong as the concentric ornamentation, about 20 in number, the two 
