456 THE NERVOUS SYSTEM. 
Fig. 3), and are only connected with the rest of the brain by 
two pairs of bundles of fibres, the peduncles and the pedicles. 
The Peduncle isa short, thick, round cord, which enters the 
under side of the procerebral lobe (Pl. XXX., Fig. 1) near its 
inner angle, and connects it with the thalamic lobe. It receives 
a considerable bundle of fibres from the trabecula, and another 
from the antennal (olfactory) ganglion. 
The Pedicle is a slender bundle of fibres, which passes from 
the nodulus to the procerebral lobe (Pl. XXIX., Fig. 1). 
The Commissure of the procerebral lobes is a thick median 
band of. transverse fibres, which connects the two procerebral 
lobes with each other; it lies immediately behind the com- 
missure of the antennal ganglia. 
The Nodulus (Pl. XXIX., ”) is a very remarkable spheroidal 
body, which is connected with the hilus of the corpus centrale 
by a single slender, round, median cord. This cord, which 
may be termed the fillet of the nodulus, consists of fibres 
which radiate from each other in the substance of the corpus 
centrale. They apparently pass through the nodulus into the 
pedicles of the procerebral lobes. 
DESCRIPTION OF PLATE XXX. 
Details of the anatomy of the brain of the Blow-fly imago. All the figures in this and 
the three succeeding plates were drawn from sections to the same scale with a 
camera lucida and a half-inch objective. 
Fic. 1.—A frontal section of the brain of an adult Blow-fly, between the antennal 
ganglia and the corpus centrale, drawn from the tenth section of a series numbered 
from before backwards. The plane of the section is slightly oblique from before 
backwards and above downwards: c/, procerebral lobe ; cv, outer fibres of the 
crus ; 7, frontal lobe of mesocerebron ; ¢, infra-cesophageal ganglia; m, lateral 
lobe of mesocerebron ; 7, nodulus ; ¢4, thalamon ; ¢”, trabecula ; 7/7, internal 
tubercle ; /a, anterior tubercle. 
Fic. 2.—An oblique section of the brain of a Blow-fly, making an angle of about 45° 
with the frontal plane. The plane of the section is from above and behind, 
downwards and forwards. It passes through the posterior part of the corpus 
centrale behind and below the brachia: ¢ c, corpus centrale ; 7, infra-cesophageal 
ganglion ; #, superior lobe of the mesocerebron; m/, internal medullary mass 
of the optic ganglion ; 7, peduncle of the corpus centrale; ¢#, thalamon; ¢7, 
trabeculae, 
Fic. 3.—A lateral section of the same, immediately above the cesophagus: a, an- 
tennal lobe; cv, ascending fibres of the crus ; yg c, ganglion of the crus, with 
two bundles of ascending fibres on its inner surface; ¢, lower lobe of the 
thalamon. 
