48 SPECIAL ANATOMY OP THE TERRESTRIAL 



rate nuclear bodies resemble the nuclei of the ganghon 

 globules, but are much smaller, and contain but a 

 single nucleolus. The nerve fibres pass through the 

 ganglionarj centres, among the globules in every direc- 

 tion ; but none of them appear to originate or terminate 

 in the latter. None of the ganglionarj cells are cau^ 

 dated. 



The nerves consist of bundles of tubuli, containing an 

 oleo-albuminous matter, which in the fresh nerve is semi^ 

 fluid, faintly granular, homogeneous, and translucent, but 

 after the matter is pressed out of the tubuli it separates 

 into two portions, one of which is a tenacious, fluid sub- 

 stance, containing the other in the form of oil-like glo^ 

 bules of no determinate size. The wall of the tubuli is 

 amorphous and transparent, and has attached to it, and 

 projecting externally, oval, granular, nucleolated nuclei. 



The nerves, especially in those emanating from the 

 supra-oesophageal ganglia, are enveloped in a sheath 

 formed of large, elongated, polygonal, transparent cells, 

 containing in the centre an oval nucleus surrounded by 

 a mass of coarse, granular bodies, which are endowed 

 with a very active molecular movement. 



Chapter x. — on the organs of especiai; sense. 



Touch. The soft, mucous integument is very irrita- 

 ble ; but tactile sensibility is most developed in the ten- 

 taculae, which are two pairs of tubular prolongations of 

 the external integument, from the anterior part of the 

 body or head. The superior pair of tentaculae are 



