Hiatella. 
MOLLUSCA. SOLENID.E. 
461 
Tellina depressa, Penn. Brit. Zool. iv. 87* t. xlvii. f. 27 — T. variabilis, 
Don. Brit. Shells, t. xli. f. 2 . — S. vesp. Mont. Test. Brit. 54. — Psam- 
mobia vespertina, Turt. Biv. Brit. 92. t. vi. f. 10 — Southern coasts of 
England and Zetland. 
Length an inch and a half, breadth 3 inches ; opaque ; cuticle dark-brown, 
with purplish longitudinal rays ; striae on the retral extremity coarse ; a slight 
oblique fold from the beaks to the hinder extremity ; one of the teeth in one 
valve thin, laminar, and oblique. 
57^. S. dejlorata . — Valves convex, obsoletely truncated re~ 
trally, with numerous waved longitudinal striae, crossed by the 
layers of growth. 
Venus defl. Linn. Syst. i. 1133. Penn. Brit. Zool. iv. 96. t. Ivii. f. 54. 
Mont. Test. Brit. 123. t. hi. f. 4. — Psammobia defl. Turt. Biv. Brit. 93. 
South coast of England, rare. 
Length an inch, breadth an inch and three quarters ; purplish ; from the fold 
to the margin behind the cartilage, the longitudinal striae are large and rough 5 
two teeth in each valve, one of them small. 
EXTINCT SPECIES. 
1. S. Hollowayisn Depressed, transversely elongate, ovate, and striated ; 
posterior side gradually expanded ; anterior side very small. — Sower. Min. 
Conch, t. clix. — London Clay. 
2. S. undulata. — Three times as wide as long, transversely undulated ; con- 
vex ; anteriorly rounded, posteriorly subtruncate, gaping a little ; beaks pro- 
minent — Sower. Min. Conch, t. Dxlviii. f. 1, 2. — Inferior Oolite. 
3. S. gihhosa — Three times as wide as long, gibbose, smooth ; sides rather 
acuminated, a little gaping, — Sower. Min. Conch, t. Dxlviii — Carboniferous 
Limestone.) Queen’s County, Ireland. 
Gen. CXXXVII. HIATELLA.— Transversely oblong ; dor-, 
sal and ventral margins nearly parallel; hinge with the 
teeth obscure, or with one tooth in one valve received into 
a cavity in the other. 
573 . H. rugosa. — Hounded anteally, subtruncated retrally, 
with a slight constriction towards the middle of the ventral mar- 
gin. 
Pholas noster. List. An. Ang. 172. t. iv. f. 21. — Mytilus rugosus, Linn, 
Syst. i. 1156. Mull. Prod. 249. Zool. Dan. t. Ixxxvii. f. 1, 2.— Mya 
byssifera. Fab. Green. 408. — Mytilus rugosus, Penn. Brit. Zool. iv. 
110. t. Ixiii. f. 72 . Mont. Test. Brit. 164. — Saxicava rugosa and S. Pho- 
ladis, Turt. Biv. Brit. 20. t. ii. f. 10.— In cavities of limestone and the 
roots of fuci. 
Length half an inch, breadth an inch and a half ; white, with a greyish 
wrinkled cuticle ; irregularly sulcated concentrically ; the ridges most conspi- 
cuous on the angle from the beaks to the retral extremity ; the animal em- 
ploys a byssus, when not lodged in the cavity of a stone. 
574. H. arctica. — Shell with two diverging spinous ridges 
from the hinge to the retral extremity. 
