86 
ROOM XII. 
Nat. Hist. 
ROOM XIII. 
Nat. Hist. 
of which are peculiar for the foot being small, and 
furnished with a tuft of fibres at its base in front, by 
which the animal fixes itself to rocks, &c. This 
beard, as it is called in the last genus, issues out 
of a groove in the front of the right valve. The Pinnae, 
like the Pond Muscles, differ according to the place 
they inhabit. Those which live in smooth water are 
thin and covered with rows of small scales, while 
those that are found in rough water are thick and 
rugose. 
Then follow the genera Area, Pectunculus and Nu- 
cula, the animals of which have a large foot divided 
at the end, and the hinge formed of many interlocking 
teeth. In Area the end of the foot forms a glutinous 
secretion, which at length hardens, by which the animals 
attach themselves to rocks, &c.; and the shell is rhom¬ 
bic. In Pectunculus , the shell is orbicular, and the hinge 
line curved, while in Nucula , the hinge line is angular, 
with the cartilage placed in a pit at the angle. 
Lastly are placed the shells of the Branchiopodous 
Mollusca, which have two ciliated arms, one placed 
on each side of the mouth. Of these, of which only 
two genera are found in Britain, viz. Terebratula 
and Criopus, the first is affixed by a tendon passing 
out through a hole in the upper valve, and the other 
is attached by the outer surface of its under valve. 
THIRTEENTH ROOM. 
The upright glazed Cases round the room contain 
the general collection of Birds. 
Cases 1 to 12 contain the Raptorial or Birds of 
Prey, the Accipitres of Linnasus, which constitute the 
first Order. They are characterized by strong feet 
with sharp claws, and a powerful bill, the latter co¬ 
vered at the base by a naked skin, or cere ; their sto¬ 
mach 
