THE ORGANS OF THE SENSES. 289 



with the brain by one only, but tolerably robust nerves. Two branches 

 originate posteriorly from them, but which speedily reunite in a smaller 

 ganglion (d* e?*), which then sends off a long, rather strong filament. 

 This filament runs down by the side of the oasophagus, and passes with 

 it into the prothorax. The oesophagus here distends into the crop, and 

 about the centre of which, each nerve forms a small ganglion (f-f-), 

 from which two furcate branches, which embrace the oesophagus, pro- 

 ceed : the nerve then runs undivided on until it attains the end of the 

 crop. Here it forms the second ganglion (g. g.), which again sends off 

 three double branches, each of which furcates. The branches of these 

 furcate nerves, six in number, or twelve on both sides, pass between the 

 six caeca lying at the orifice of the stomach, and distribute themselves 

 over them in the most delicate threads. In Gryllus hieroglyphicus, 

 according .to M tiller *, the upper ganglion is again found, but its rela- 

 tive proportion is not very evident from his representation ; the nerve 

 running down the oesophagus has no ganglia, but many fine branches 

 are given off along its whole course In Achela Gryllotalpa t, the 

 downward running nerves are very distinct : both give off auxiliary 

 branches, particularly to the sack-shaped distended crop. In the 

 proventriculus, they again unite to form a tolerably considerable 

 ganglion, whence many branches originate, which distribute themselves 

 over it. Blalta and Mantis have but a central single nervous cord, 

 which appears, however, to proceed from the ganglion lying behind the 

 brain. 



IV. THE ORGANS OF THE SENSKS. 

 192. 



OF all the several organs of the senses, the eye alone possesses a 

 superior development : nose and ear are not yet proved to exist, and 

 taste likewise can be present only in a few, at least to a degree worthy 

 of investigation ; but touch, which never properly possesses a distinct 

 and constant organ, but, according to the differences of animal 

 organisation, is sometimes imparted to one and sometimes to another 

 organ, has, in the majority of the orders, peculiar organs varying in 

 their grade of development. 



Of these senses, we will first examine that of sight, as the most 

 perfect. 



* PI. IX. f. 5. f Ib. f, 2. 



u 



