326 GINGLYMACONCHA. UNIONIDA. 
the Medway, in the Mole, near Cobham in Surrey, in the Nor- 
folk localities mentioned above, in the Wye at Hereford, and 
in the Cam at Cambridge: in the last-mentioned localities it 
occurs but sparingly. These were sent to me by my friend Pro- 
fessor Henslow of Cambridge. 
Genus 62. ANODONTES. 
Anodontes, Bruguicre, Cuvier. 
Anodonta, Lamarck, Say, Rafinesque, Xe. 
Shells equivalve, equilateral, elongate; the hinge straight 
and toothless ; the cardinal lamina is smooth, anteriorly trun- 
cated or ending in a sinus, terminating the anterior aspect: the 
two muscular impressions are lateral, remote from one another, 
and paired or doubled; the cardinal ligament is straight exte- 
riorly, with its anterior extremity passing down in a sinus of the 
cardinal ligament. 
The orbicular muscles of the mantle are united behind the 
posterior and above the anterior adductor muscle ; the branchiz 
are unequal; the exterior ones smallest, and connected at 
their hinder extremities with the orbicular muscles, forming 
the superior respiratory or tracheal tube complete and entire : 
the abdomen is covered with a very thin membrane ; the foot 
is acuminated and lamelliform. 
1. ANODONTES EvuROPA. 
Shells with their valves somewhat ovately wedge-shaped, 
behind (especially in the young ones) with angulated wings ; 
the epidermis fuscous inclining to luteous, radiated with black ; 
or brown or intense deep black-brown, and not radiated. 
Mytilus cygneus, Lister, Anim. Angl. App. t. 1. f. 3; Conch. 
t. clv. f. 11; Gualt. Test. t. vii. f. F.; D’Argenv. Conch. 
t. xxxi. f. 10, sin. ; Penn. Brit. Zool. iv. 113. t. lxviii. f. 78; 
Da Costa, Brit. Conch. 214. t. xvii. f. 2; Schroét. Fluss. 
t. i. f. 1; Hinl. ii. 440; Chem. Conch. vii. t. Ixxxvi. f. 
763; Gmel. Syst. Nat. 3355 ; Pult. Cat. Dorset. 38. t. xi. 
f. 2; Drap. Hist. Nat. des Moll. terrest. et fluv. 134. t. xii. 
