18 INTERNAL ANATOMY OF INSECTS. 
ing the first a ; and at the same time he gives it as his 
opinion, that all the nerves in insects really originate 
from the marrow itself, and not from the ganglions, which 
he asserts are of a different substance, and are inclosed 
in the marrow for the sake of giving it greater firmness b . 
In this opinion, however, he seems singular c . Those re- 
markable nerves described by Lyonet under the name 
of spinal bridle (bride epinierc) also take their origin, not 
from the ganglions, but from a bifurcation of the spinal 
marrow. Of these, in the caterpillar of the goat-moth 
there are ten, the first issuing from the bifurcation of 
the internode between the fourth and Wth ganglions, and 
the remainder from the succeeding ones. After approach- 
ing the succeeding ganglion, these nerves form a pair of 
branches that diverge nearly at right angles from the 
bridle, and producing several lesser branches, lose them- 
selves in the sides of the animal d . Besides the nerves 
above mentioned, two generally issue from the poste- 
rior part of the last ganglion, diverging in opposite and 
oblique directions : some of these render to the parts of 
generation ; and in the silk-worm, and probably other 
species, the innermost pair is perforated for the passage 
of the vasa deferentia e . 
a In Mr. Bauer's figure (Pkilos. Trans. 1824. t. W.f. 1 .) no less than 
eighteen pairs of nerves are represented as issuing from the inter- 
nodes ; but it should seem as if in the specimen from which his figure 
was taken, several of the ganglions, perhapsfrom some injury received 
in the dissection, had become obliterated, while their nerves remain- 
ed •. yet still, even making allowance for these, many pairs will appear 
to take their origin from the spinal chord. 
b Comp. Cuv. Anat.Comp. ii. 102 — 123.; with Swamm. Expl. of 
Plates XXXII. t. xxviii./. 3. k. 
c Malpighi seems, however, to agree with him. Dc Bombyc. t. yi.f. I. 
A Lyonet ubi supr. 201. t. fat./ 1, 2. n. 1, 2. &c. 
c Swamm. tibi supr. 1. 139. a. /. xxviii./. 3. s,s. 
