I3':i CLASS INSECTA. 



of fourteen articulations and upwards ; a mouth composed 

 of two mandibles, provided with a small appendage, in the 

 form of a palpus, presenting in their centre the appearance of 

 a synostosis, and terminated like the bowl of a spoon in- 

 dented on the edges ; one quadrifid lip,* the two lateral divi- 

 sions of which are larger, annulated transversely, similar to 

 the membranous feet of caterpillars ; two palpi, or little feet 

 united at their base, unguiculated at the end ; and a second 

 lip-f- formed by a second pair of feet, dilated and joined at 

 their origin, and terminated by a strong crotchet, mobile, 

 and pierced under its extremity with a hole, for the issue of 

 a poisonous fluid. 



The body is depressed and membranous. Each of its rings 

 is covered with a coriaceous and cartilaginous plate, and has, 

 for the most part, but one pair of feet. In this case, how- 

 ever, they are but semi-rings. The last pair is usually 

 tlirown backwards, and elongated in the form of a tail. The 



* A piece analogous to the lower lip of the chylognatha, representing, 

 in my opinion, the tongue of the Crustacea, but also fit to perform the 

 office of jaws. This is what M. Savigny names first auxiliary lip. 



f The second auxiliary lip of M. Savigny. It is not joined with the 

 head, but with the anterior extremity of the first semi-segment. The two 

 feet with crotchets form, by their union and dilatation of their first articu- 

 lation, a plate in the form of a chin and lip. The same semi segment bears 

 the two first common feet. In the scolopendrae proper of Dr. Leach, the 

 first two stigmata are situated on the third semi segment. The second 

 and the following, will compose the first complete ring, and then the first 

 two stigmata will be placed, as in the other insects, in a space correspond- 

 ing to the prothorax. This second auxiliary lip may thus represent the 

 lower lip of the grinding hexapode insects; but here the pharynx is si- 

 tuated in front of this lip, whereas, in the myriapods, it is placed in front 

 of the first auxiliaty lip. It is from these relations, and many others fur- 

 nished by the entomostracea and arachnida, that I consider the feet of 

 the hexapod insects as the analogues of the six jaw-feet of the decapode 

 Crustacea. 



