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 epiniere] 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 andWth 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 defer entia e . 



a In Mr. Bauer's figure (Ph'ilos. Trans. 1824. t. ii./. 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. 102123.; with Swamm. Expl. of 

 PLATES XXXII. t. xxviii./. 3. k. 



c Malpighi seems, however, to agree with him. JDe Bombyc. /. \i.f. 1. 



d Lyonet ubi supr. 201. t. ix./. 1, 2. n. 1, 2. &c. 



c Swamm. ubi supr. 1. 139. a. t. xxviii./. 3, s } s. 



