462 EXTERNAL ANATOMY OF INSECTS. 
been denominated *, of the Arachnida, their mandibles. 
The palpi are pediform, and the first joint of the coza, 
or hip, acts the part of a mazilla :—this is composed of 
a single piece or plate, more or less oval or triangular, 
sometimes straight and sometimes inclined to the /abium, 
with the interior extremity very hairy. The labiwm con- 
sists also of a single piece, and is only an appendage of 
the anterior extremity of the breast. The interior of 
the mouth, or palate, presents a fleshy, hairy, linguiform 
piece, which is usually applied to the internal face of the 
labium. An opening is supposed to exist in its sides, for 
the transmission of the alimentary juices’. If you ex- 
amine the under side of the body of a scorpion, you will 
find that not only the palpi, but the two anterior pair of 
legs, by means of their cove, are concerned in mandu- 
cation: so that these insects have in fact three pairs of 
maxilla—a circumstance that M. Savigny has observed 
to take place also in the harvest-men (Phalangium) *. 
The palpi of the scorpion, which may be called its hands, 
like the anterior legs of the lobster and crab, terminate 
in a tremendous chela or forceps, consisting of a large 
triangular joint, armed at the end with a double claw 
internally toothed ; the exterior one of which, contrary 
to what takes place in the animals just named, is move- 
able, and not the znterior 4. ‘ 
Having given you this full account of the trophi of 
those animals that have all the organs of manducation 
developed, I must next advert to those in which one part 
receives an increment at the expense of others, and the 
aN. Dict. d’ Hist. Nat. ii. 276. » Tbid. 
© Ubi supr. 58. 4 Prats XV. Fic. 7. 
