69 
valves vary in length, but are fully three times as wide as 
long, i.e., the longitudinal measurement is one-third that of 
l one. 
; —Very narrow, and thickly clothed with minute, 
irregular, flattened scales, which do not appear to imbricate. 
Darkish blotches are noticeable opposite each suture. 
easurements.—The shell in the dried specimen is 54 mm. 
y 3 mm.; it is more than likely that a live specimen would 
measure 6 by 34 mm. 
Locality.—I am indebted to Dr. Torr for the specimen 
"Tapley Shoal, living on Zostera.” This shoal is about 6 miles 
from Troubridge lighthouse, south of Yorke Peninsula, in 
South Australia. 
General colour.—Serpentine green (Ridgway’s Colour 
Standards, pl. xvi.). The valves 2 to 4 have the dorsal area 
outlined with a broad V-shaped white mark. lor 
and apical portions of anterior valve are white The sides 
are broad] irregularly banded with white. The girdle 
irregularly-spaced blotches in front of same valve. : 
Shell.—The shell is more beaked than is the case with 
. ‘he type, and there is a slight elevation of the dorsal area 
near the beak in the first four valves. Starting at the posterior 
Margin of the beak are a few shallow, circular elevations, 
Which die away towards the middle of the anterior portion 
of the lateral area. These elevations are only seen in some 
lights with a high-power lens. The whole shell is highly 
Polished and transparent. ! 
