15 
left valve, broadly compressed, rather rounded, and pro- 
jecting almost, vertically ; a cardinal pit in the other valve. 
Ligament internal, inserted in the prominent tooth and 
the corresponding pit. 
A1 - TRUNCATA. Turt. Lin. Pen. Brit. Zo., vol. 4, pi. 41, 
%. 14. Stew. F.lem., vol. 2. p. 336. Mont. Test. Brit., 
v °l. 1, p. 32, Flcm. Brit. An. p. 162. Rare. 
ANATINA. 
°ENERIC CHARACTER: Shell transverse, with nearly 
e qual valves, gaping at one or both sides; one naked, 
hfoad, spoonshaped, cardinal tooth, projecting internally, 
>n each valve, and receiving the ligament. In many species 
a lamina or falcated rib runs obliquely below the cardinal 
teeth. 
J • MYALIS. Mya Pubescens. Mont. Test. Brit., vol. 1, 
P- 40. Ampkisdesma P. Flem. Brit. An., p. 431. 
Anatina M. Crouch’s Introd., pi. 4, fig. 1. 
S j M°ntagu says, “this species is not uncommon, of small 
Ze >, taken up with sand from Falmouth harbour — one we 
^ Ce!v ed from Plymouth, taken by dredging, was 2 inches 
.| r °ad, and Ji long.” It is otherwise rare; but 1 obtained 
a Pal mouth, above 2| inches broad. 
• DECLIVJS. Marked for me at the British Museum, 
— ^ " *■ v j v* ui i\V/U iui tuu at tut/ ut itistl mu 
, ut which I am not able with confidence to refer to any of 
he usually received synonyms of this shell: considered, as 
Usually is, as the young state of the last species. Pennant, 
Aontagu and Fleming, are entirely at variance on this 
^fiject; and until more information is obtained, it is best 
e report it simply, as not of common occurrence within 
le sphere of my observation. 
SECTION II. 
Ti 
o t le foot small, compressed ; Lobes of the mantle scarcely 
g etl 0ot a t all united in front. Lateral gaping of the shell 
e rally inconsiderable. 
T M ACT RACE A. 
e Xtr equal valves, generally gaping at the lateral 
li»T^ niu * es - Ligament internal, with or without an external 
sanient. 
Gb LUTRARIA. 
t rari ^'Lf/C CHARACTER: The shell with unequal sides, 
hi 
an sversely oblong or rounded, lateral extremities gaping; 
atb, one of 
^1 ? e with one tooth folded in two ; or two teeth, 
pro' C * -* S s ' m pl e > with an adjoining, deltoid, oblique pit, 
inwards; no lateral teeth. Ligament internal, 
L Vit " 1 l * ie P’ ts ' 
R r j, LGARIS. Mactra Lutraria. Turt. Lin. Pen. 
£o -> vol. 4, pi. 52, fig. 44. Stew. Elem., vol. 2, 
