486 MANUAL OF THE MOLLUSCA. 
Sub-genera. ? Amphichena, Phil. A. Kindermanni, California, 
Shell oblong, nearly equilateral, gaping at each end; teeth 43 
ligament external, pallial line sinuated. 
Iphigenia, Schum. (Capsa, Lam., 1818, not 1801. Donacina, 
Fér.) I. Brasiliensis, Pl. XXI., Fig. 20. Shell nearly equi- 
lateral, smooth ; hinge-teeth 2.2, one bifid, the other minute ; 
laterals remote, obsolete in the left valve; margins smooth. 
Distribution, 5 species. West Indies, Brazil, West Africa, Pacific, 
Central America. Inhabits estuaries. J. ventricosa, Deshayes, 
is rayed like Galatea, and has its beaks eroded. 
? Isodonta (Deshayesu). Buy. Bull. Soc. Geol. Oolite. 
France, England. 
GALATEA, Bruguiére 
Synonyms, Egeria, Roissy. Potamophila, Sowerby. Mega- 
desma, Bowdich. 
Type, G. reclusa, Pl. XXI., Fig. 21. 
Shell very thick, trigonal, wedge-shaped ; epidermis smooth, 
olive; umbones eroded; hinge thick, teeth 1.2, laterals indis- 
tinct; hgament external, prominent; pallial sinus distinct. 
Animal with the mantle open in front; siphons moderate, 
with 6—8 lines of cilia, orifices fringed ; foot large, compressed ; 
palpi long, triangular; gills unequal, united to the base of the 
siphons, the external pair divided into two nearly equal areas 
by a longitudinal furrow, indicating their line of attach- 
ment. 
Distribution, 6 or 7 species? Wile, and rivers of West Africa. 
FAMILY XVII.—SOLENIDZ. 
Shell elongated, gaping at the ends; ligament external; 
hinge-teeth usually 2.3, compressed, the posterior bifid. External 
shell layer with definite cell-structure, consisting of long prisms, 
very oblique to the surface, and exhibiting nuclei; inner layer 
nearly homogeneous. 
Animal with a very large and powerful foot, more or less 
cylindrical ; siphons short and united (in the typical Solens, with 
long shells) or longer and partly separate (in the shorter and 
more compressed genera); gills narrow, prolonged into the 
branchial siphon. 
SouEN (Aristotle), L. Razor-fish. 
Type, 8. siliqua, Pl. XXII., Fig. 4. 
