Lamarck’s Genera of Shells, 85 
protruding a large tube, containing two others, one to admit 
water, the other for the anus. 
Linneus confounded in one genus the mya and unio; where- 
as, the latter is a fresh-water shell, and has a very different 
hinge from that of the mya. The myz bury themselves in the 
sand. 
Type. Mya truncata*. Idem Linn. 
Shell ovate, ventricose, anteriorly truncated; cardinal tooth 
very entire, rounded, projecting forward. Luropean Ocean. 
Pl. iv. Fig. 29. 4 Species. 
2. Anatinat. 
Shell transverse, subequivalve, gaping at one or both sides. 
One naked, broad, spoon-shaped cardinal tooth, projecting 
internally in each valve, the hollows of which receive the liga- 
ment. Generally a lamina, or falciform rib, near the hinge 
teeth, and running obliquely below them. 
The anatina differs from the mya, by having two spoon-shaped 
teeth, whilst the mya has but one. 
Type. Anatina lanternat. 
Shell ovate, very thin, pellucid, fragile, rounded on both 
sides. Indian Ocean. Pl. iv. Fig. 30. 10 Species. 
Section II. 
TENUIPEDAS. 
Lobes of the mantle scarcely or not at all united in front; 
foot small, compressed. Lateral gaping of the shell generally 
inconsiderable. 
This section includes several of the conchifera, hitherto 
very confusedly arranged. Some were united to the solens, to 
which they seemed nearly allied, although the animal, especially 
in its foot, probably differs very much in form and proportion 
from the inhabitant of those shells. Others were placed with 
the myz, tellinee, and veneres, and a great number were still 
without any proper place being assignable to them amongst 
the existing genera. To get rid of this confusion, Lamarck 
*" Truncated. + From anas, a duck? t Lantern. § Slender-footed. 
G2 
