GINGLYMACONCHA. PHOLEOBIADZ. 255 
cblique process ; that of the left side largest. One large ac- 
cessory shell covers the anterior adductor muscle entirely. 
BARNIA CANDIDA. 
The shells with radiating and concentric elevated strize, which 
at their junctions, especially anteriorly, have elevated spines. 
Length two inches and three quarters; height three-quarters 
of an inch. 
Pholas candida, Linn. Syst. Nat. xu. 1111. no. 22; Penn. 
Brit. Zool. iv. 76. t. xxxix. f. 11; Da Costa, Brit. Conch. 
246; Pult. Cat. Dorset. 26. t.1.f. 12; Donov. Brit. Shells, 
t. exxxul. ; Mont. Test. Brit. 25 ; Flem. Edinb. Encycl. vii. 
100; Dill. Desc. Cat. 36; Turt. Conch. Dict. 144; Wood, 
Gen. Conch. i. 78. t. xiv. f. 3, 4. 
This species is extremely common on the south-western coasts 
of England. It perforates wood in the Kingsbridge Estuary, 
and the red sandstone at Dawlish. Length from two to two 
and three-quarter inches ; height half an inch. 
I have never seen the animal of this species. 
FAMILY II. PHOLEOBIADZ. 
Shell equivalve, subelongate, gaping either anteriorly or pos- 
teriorly. Umbones anterior; hinge ligament hinge-shaped ; 
hinge generally without teeth; epidermis thin, covering the 
respiratory tubes, which are subcylindric, equal, very long and 
attached to each other; foot very short, ovately depressed ; 
orbicular muscles entirely united, excepting at the exit of the 
foot. 
All the genera of this family inhabit the sea, and either per- 
forate rocks or shells, or reside in the cavities formed by other 
animals, or amongst the thick roots of marine plants. 
