442 MOLLUSCA. 
~ 
Length two and a half inches; height two and a quarter inches; 
breadth three-fourths of an inch. 
Inhabits New Zealand. 
In form it resembles A. /urida; but its smoother surface, difference 
of coloration both without and within, and its much more elongated 
auricle, are quite distinctive. The young stages of this shell are 
exceedingly beautiful, being rose-red, with a sort of superficial radia- 
tion of cream-colour. 
Figures 551, 551 a, two views of the shell. 
AVICULA GLABRA (Gould). 
T. tenuis, semi-elliptica, vix obliqua, valde caudata, glabra, ad periphe- 
riam lamellata, virescens, albo-radiata: valva dextra planiuscula ; 
auricula latior quam longa: valva sinistra ventricosa, anticé integra, 
acutangula: cardinis dentibus obsoletis: margarita argentea; limbo 
corticalt livido-corneo. 
Avicula glabra, Goutp; Proceed. Boston Soc. Nat. Hist., iii. 310. 
Dec. 1850. Expedition Shells, 91. 
SHELL very thin and fragile, spade-shaped, slightly oblique; left 
valve rather ventricose ; right nearly flat; surface generally smooth and 
shining ; somewhat loosely laminated near margin, and with ranges of 
distant minute scales, in young specimens; colour pale beryl-greenish, 
with opaque white radiations; dorsal edge long and straight, slightly 
produced into a queue, from which the posterior edge, after a slight 
inflection, descends directly at right angles; base broadly rounded ; 
anterior edge a little oblique; ear triangular, closely and loosely 
striated ; re-entering angle obtuse; nacre silvery white; shelly margin 
pale greenish or ochreous; no perceptible cardinal tubercle, and with 
a short lateral ridge simulating a tooth ; byssal edge largely open; op- 
posing tubercle slight, almost without umbonal ridge. 
Length and height two and three-fourths inches; breadth seven- 
eighths of an inch. 
