SPECIAL ANATOMY. 043 
rate nuclear bodies resemble the nuclei of the ganglion 
globules, but are much smaller, and contain but a 
single nucleolus. The nerve fibres pass through the 
ganglionary centres, among the globules in every direc- 
tion ; but none of them appear to originate or terminate 
in the latter. None of the ganglionary cells are cau- 
date d. 
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 especial sense. 
Touch. The soft, mucous integument is very irrita- 
ble ; but tactile sensibility is most developed in the ten- 
taculre, 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 
