16 DEFINITION OF THE TERM WSECT'. 



kind and degree of sense and intelligence that they pos- 

 sess, seems rather fanciful than founded in nature, since 

 many insects show a greater portion of them than many 

 vertebrate animals. Compare in this respect a bee with 

 & tortoise*. Lamarck divides his group oianimaux sen- 

 sible?; into two sections, namely, Articulated animals, ex- 

 hibiting segments or articulations in all or some of their 

 parts ; and Inarticulated animals, exhibiting neither seg- 

 ments nor articulations in any of their parts. Insecta, 

 Arachnida, and Crustacea, belong to the first of these 

 sections, which he defines as " those whose body is di- 

 vided into segments, and which are furnished, with jointed, 

 legs bent at the articulations 1 '." Insecta he defines — 

 " Articulate animals, undergoing various metamorphoses, 

 or acquiring new kinds of parts — having, in their perfect 

 state, six feet, two antenna, two compound eyes, and a 

 corneous skin. The majority acquiring wings. Respira- 

 tion by spiracles (stigmates), and two vascular opposite 

 chords, divided, by plexus, and constituting aeriferous tra- 

 chea:, which extend, every where. A small brain at the 

 anterior extremity of a longitudinal knotty marrow, with 

 nerves. No system of, circulation, no conglomerate glands. 

 Generation oviparous : two distinct sexes. A single sex- 

 ual union in the whole course oflife c ." Arachnida he 

 defines — " Oviparous animals, having at all times jointed 

 legs, undergoing no metamorphosis, and never acquiring 

 new kinds of parts. Respiration tracheal or branchial : 

 the openings for the entrance of the air spiraculiform 

 (stigmatiformes). A heart and. circulation beginning in 



n See on this point MacLeay, Hor. Entomolog. 209— . 



b Anhri. sans Vertebr. iii. 243. <■• JhUl. iii. 243 



