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 are so thick as to appear portions 
of the brain, which they equal in diameter b . 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 cesqphdgus, 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. 
c 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 liibl. Nat. i. 138. b. t. xxviii./. 2. «, b, cf. 3. g. 
e Ubi supr. 578. f Ubi supr. 320. 339, &c. 
