460 THE NERVOUS SYSTEM. 
‘The superior capsule descends, behind, to the same level as 
the inferior, except in the middle line, where it is deeply 
notched ; on either side of this notch a short peduncle arises, 
which immediately expands into a spherical tubercle, the 
tubercle of the corpus centrale. The opposite tubercles are 
united with each other by a short fibrous fasciculus.’ In the 
Blow-fly the peduncles of the corpus centrale are apparently 
longer. I have not been able to recognise any tubercles upon 
them, but they evidently have connections with the thalamic 
lobes as well as with the crura (see Pl. XXXI., Fig. 2). 
The Cortex of the Brain—The cellular cortex of the brain not 
only covers the whole surface witha layer of variable thickness, 
but it penetrates the interior and becomes continuous with the 
great pyramidal ganglion, with the lamina of gray matter 
surrounding the corpus centrale, and with that surrounding 
the thalamic and procerebral lobes. 
The cortex consists of cells similar to those of the thoracic 
ganglia, but the optic ganglia and the posterior part of the 
cortex are formed almost entirely of small round cells similar to 
the cortical cells of the cerebellum, and to those of the nuclear 
layers of the retina in the Vertebrata. 
The whole superior and posterior region, in which these 
small cells are largely developed, is divided into four very 
remarkable areas, two on each side, known as the corpora 
fungiformia. 
The rest of the cortex is not divided into distinct areas, but 
groups of large stellate cells occur around the roots of the 
DESCRIPTION OF PLATE XXXII. 
Fic, 1.—A frontal section of the brain of the Blow-fly, with a slight obliquity from 
above downwards and behind forwards, behind the nodulus. The upper half of 
this section is behind, and the lower half in front of the plane of the section seen 
in Plate XXX., Fig. 1. a@, antennal ganglion; ¢/, ¢ /, ¢ /, lobes of the pro- 
cerebron ; ¢#, thalamic lobe ; 7, #, »z, superior lobe of the mesocerebron. 
Fic. 2.—A similar section through the corpus centrale from the same brain: ¢ ¢, 
corpus centrale ; ¢”, ¢, brachium of the corpus centrale; 7, infra-cesophageal 
(crural) ganglia; 7, trabecula. The other references as in Fig. 1. 
Fic. 3.—A lateral section of a Blow-fly’s brain through the lower part of the corpus 
centrale : #7, mesocerebron ; m/, metacerebron ; 0 s, optic peduncle. The other 
letters as in Figs. 1 and 2. 
