ENSIS, Schumacher. 
Gen. Char. Equivalved, very inequilateral, trans- 
verse, slightly arched ; gaping at both ends, 
margins parallel, umbones close to the anterior 
extremity. Hinge with one conical erect tooth 
in the right valve, and two compressed erect 
teeth in the left valve, and an elongated trans- 
verse lateral tooth, connate with the fulcrum, 
and the erect teeth, in each. Muscular impres- 
sions, &c. as in Solen. 
The presence of the long lateral teeth in the hinge is so 
strong a character, that we cannot avoid adopting Schu- 
macher’s genus. We are not prepared to say it is positively 
a natural genus, but most, if not all, of the species are a 
little arched, and none of them have the anterior side de- 
fined by a furrow, which is so often the case in Soleji : these 
general relations, although slight, have some pretensions to- 
natural characters; moreover, the long lateral teeth, whose 
office is to steady the valves when they open, must have 
reference to some habits of the animal in which it differs 
from Solen. Solen Ensis of Linnaeus is the type of the 
genus ; it includes also S. siliqua , and a few others. 
ENSIS ensiformis. 
TAB. DCXLIl. —fig. 1. 
Spec. Char. Gently curved, thin, smooth, con- 
vex, about four times as wide as long, the two 
angles of the posterior and the lower angle of 
the anterior extremities rounded ; the poste- 
rior portion a little flattened ; the basal edge 
