16 INTERNAL ANATOMY OF INSECTS. 



is very large, cylindrical, and of a diameter equal to the 

 length of the last-mentioned part, upon the side of which 

 it is supported ; it terminates in a very large bulb cor- 

 responding to the eye a : in Scolopendra morsitans the 

 optic nerves divide into four branches long before they 

 arrive at the eyes, and in this insect the nerves which 

 render to the antennae ^re so thick as to appear portions 

 of the brain, which they equal in diameter 5 . Swammer- 

 dam discovered in the grub of the rhinoceros-beetle and 

 in the caterpillar of the silk-worm, a pair of nerves which 

 he regarded as analogous to the recurrent nerves in the 

 human subject, and therefore he distinguishes them by 

 the same name c : they issue from the lower surface of the 

 brain, or that which rests on the cesophagus, and at first 

 go towards the mouth, but afterwards turn back, and 

 uniting form a small ganglion ; this produces a single 

 nerve, which passing below the brain follows the oesopha- 

 gus to the stomach, where it swells into another gan- 

 glion, from which issue some small nerves that render to 

 the stomach, and one more considerable which accom- 

 panies the intestinal canal, producing at intervals lateral 

 filaments which lose themselves in the tunics of thattube d . 

 Lyonet afterwards discovered these nerves in the cater- 

 pillar of the goat-moth e , and Cuvier in other insects f . 



The other nerves which issue from the brain exhibit 

 no remarkable features. Those which originate in the 

 spinal marrow are mostly derived from the ganglions, and 



a Cuv. ubi supr. 351. b Ibid. 352. 



Cuvier (Ibid. 319.) seems not to have been aware that Swam- 

 merdam was the first discoverer of these nerves, since he attributes 

 their name to Lyonet. 



d Bibl. Nat. i. 138. b. t. xxviii./. 2. a, b, c.f. 3. g. 



e Ubi supr. 578. ! Ubi supr. 320. 339, &c. 



