EXTERNAL ANATOMY OF INSECTS. 4.59 
exhibit a very great one ;—and will lessen your surprise 
when you find, that in certain tribes such commutations 
of organs and their use take place. 
The following is the structure, as to its organs, of the 
mouth of the myriapods, as exhibited by the centipedes 
(Scolopendride). The part which appears to perform the 
office of the upper lip (but which M. Savigny regards 
as the nose, calling it the chaperon,) is a transverse piece 
with a deep anterior sinus, in the centre of which is a 
minute tooth?. This piece is separated from the fore- 
part of the head by a suture; but it probably is not move- 
able: however, it covers the mouth, and may be regarded 
rather as analogous to the labrum. Below this are two 
mandibles, armed at their end with five sharp triangular 
teeth, under which are the mazille, terminating in a 
moveable concavo-convex lobe, resembling the valve of 
a bivalve shell*; and between them is the /abium, of a 
rhomboidal shape, divisible into two lobes, attached la- 
terally to the maxille: these lobes M. Savigny terms the 
second maxille, forming with the others, according to 
him, the labium*. Aflixed to the base of this labium, or 
covering it on the outside, are a pair of pediform palpi, 
which he considers as the first auxiliary Zabium, and re- 
presentative of the first pair of legs of hexapods and Juli«. 
I imagine them to be also the analogues, in some degree, 
of the labial palpi of a perfect mouth. The last of the 
organs in question is a large rhomboidal plate affixed to 
the first apparent segment of the trunk, crowned at its 
* Anim. sans Vertébr. I. i. t. ii. f. 2. a. a’. 
b Prate VII. Fic. 13. c’. © Tbid. d’. 
4 Anim. sans Vertebr. 1.1. 106. Puare VII. Fie, 13. b’. 
© Ubi supr. 45— 
