464 
MOLLUSCA. MYAD^. 
Lutraria. 
4. M.. sulangulata, — Rathei* depressed, smooth; wider than long; nearly 
equilateral, oblong-ovate; an angle from the beak to the retral margin; ven- 
tral margin slightly restricted. — Soiver. Min. Conch, t. Ixxvi. f. 3. — London 
Clay. 
5. M. lata — Ovate, depressed ; retral side acuminated and truncated, 
slightly gaping. — Sower. Min. Conch, t. Ixxxi — In Crag. 
C. M ? literata. — Transversely oval, subequilateral, convex, smooth, thin, 
with obtuse angularly bent ridges on the central part ; angles of the ridges 
in a longitudinal direction.—- ParA:. Org. Rem. iii. 196. t. xiii. f J6. — Sower. 
Min. Conch, t. ccxxiv. f 1. — Inferior Oolite. 
7. M ? scripta. — Transversely oval, subequilateral, convex, smooth, thin, 
with oblique angularly bent ridges on the central part ; angles of the ridges 
in an oblique direction. — Sower. Min. Conch, t. ccxxiv Inferior Oolite. 
8. M ? angulifera — Transversely elliptical, elongated, gibbose, with oblong 
angularly bent ridges upon the surface, retral half widest, gaping ; angles of 
the ridges acute, in an oblique direction — Sower. Min. Conch, t. ccxxiv. f. 6, 
7. — Oolite. 
9. M ? gregaria. — Obovate, convex, subdeltoid, smooth ; retrally produced 
and truncated.— Min. Conch, t. ccclxiii. — Upper fresh water Formation^ 
Isle of Wight. 
10. M. arenana.’-^Sower. Min. Conch, t. ccclxiv. and t. Dxxxi. f. 2. — iVb?‘- 
folk and Suffolk Crag. 
11. M.. depressa — Obovate, depressed, very slightly gaping ; anterior side 
shortest ; beaks prominent incurved, hinge-line straight, depressed Sower. 
Min. Conch, t. ccccxviii. — Middle Oolite. This is probably a Panopcea^ as it 
is stated that the ligament is external and short. 
12. M-.gihhosa — Obovate, transversely furrowed, gibbose; beaks prominent, 
incurved ; anteal side very short ; retral side rather attenuated and gaping. 
— Sower. Min. Conch, t. ccccxix. — Middle Oolite. 
13. M. Oblong, ventricose, straight, anterior side short, and trans- 
versely plaited ; posterior gaping, truncated — Sower. Min. Conch, t. ccccxix. 
f. 3 Green Sand. 
14. M ? angustata. — Valves unequal; transversely elongated, thin, anti- 
quated, irregularly compressed ; extremities obtuse, gaping ; lower edge of 
the lesser valve concave.— *S'o^^7er. Min. Conch, t. nxxxi. — Upper marine For- 
mation^ Isle of Wight. 
Gen. CXL. — -LUTRARI A. — Equivalve, transverse, gaping ; 
hinge with a broad vertical plate for the cartilage, sup- 
porting one or two teeth on its anteal margin. 
580. L. vulgaris . — Nearly equilateral, and rounded at both 
extremities. 
Concha longa. List. An. Ang. I70. Conch, t. xiv — Mactra lutraria, 
Linn. Syst. i. 1126. Penn. Brit. Zool. iv. 92. t. iii. fl 44. Mont. Test. 
Brit. 99 Lutraria elliptica, Turt. Biv. Brit. 65. — In sand about low- 
water mark. 
Length 2^ inches, breadth 5 ; yellowish-white, with a thin close cuticle ; 
slightly striated concentrically by" the layers of growth, with remote obsolete 
ridges. 
