THE BRAIN OF THE LOCUST. 241 
that there is a partial nervous communication between the trabecular and 
the commissural lobes. The libers enveloping the trabecula above are 
more numerous, the mass of fibers much thicker than in section 10, 
Showing that what we supposed to bo libers separating the stalk from 
the trabecula appear to bo really such. 
A broad bundle of fibers is also seen on the right side, passing down 
from the upper side inside of the upper end of the peduncle, down out- 
sido and back of the central body, and to enter the commissural lobe on 
its inner side, terminating at the point where the ascending fibers to the 
npper side of the trabecula originate. There is thus a direct communica- 
tion between the upper part of the brain and the oesophageal commissure 
in the lower part. It appears, also, that three large nerves or bundles 
of fibers enter each commissural lobe from above. 
At the under side of the commissural lobes the cortical ganglion cells 
(some of them very large) appear to send their fibers into others to build 
up the mass of fibers enveloping the lobe. Flogel states that the opinion 
that the ganglionic cells in winged insects are in direct relation through 
the fibers with the organs of the body are unfortunately provisionally 
contradicted by his observations. But here (seen in a portion of the 
commissural lobe not represented in Fig. 3 of PI. XI), as in one or two 
other places, we think we have seen fibers from the cortical ganglion cells 
passing into and aiding in building up the nerves. Such a relation is 
very plain in the brain of the horseshoe-crab, Limulus polyphemus. 
LIST OF WORKS ON THE INTERNAL STRUCTURE OF THE BRAIN OF 
CRUSTACEA AND INSECTS. 
Dujardin. Memoirs sur le Systeme nerveaux des Insectes. Par. F. Dujardin. An- 
il ales des Sciences naturelles. Ser. 3. 1850. Tom. xiv, p. 195-206, tab. 1, 1850. 
Ofsianxikoff. Ueber die feinerer Structur des Kopfganglions bei den Krebsen, be- 
sonders boim Palinurus locusta. Von Ph. Ofsiannikof. Mem. Acad. Imp. Sc. St. 
Petersbourg. Tom. vi, No. 10, 1863. Plate i. 
Leydig. Voni Ban des thierischen Korpers. Von P. Leydig. Tubingen, 1864, p. 
214-226. 
Rabl-Rlxkuaiid. Studien uber Iusecteugehirne. Von Rabl-Ruckhard. Archiv fur 
Anatomic, Physiologic, etc., herausg. von Reichcrt u. R. Du Bois-Raymond, Jan. 
1876, p. 480. Plate i. 
Dietl. Dio Organization des Arthropodengehirns. Von M. J. Dietl. Zeitschr. wis- 
sensch. Zool. Bd. 27, 1876, p. 488. Plates xxxvi-xxxviii. 
Berger. Memoir, by E. Bergcr, in Arbeiten des zoologischen Iustituts zu Wien. Bd. 
i, Heft, ii, p. 173, 1878. 
FLOGEL. Ueber den einheitliehen Bau des Gehirns in den verschicdenen Insecteuord- 
nungen. Von J. H. L. Flogel. Zeitschr. wissensch. Zoologie. Bd. xxx, suppl. 
1878, p. 556. Plates xxiii, xxiv. 
Newton. On the Brain of the Cockroach, Blatta orientalis. By E. T. Newton. 
Quart, Journ. Microscopical Science, July, 1879, p. 340. Plates xv, xvi. 
Graber. Ueber das unicorneale Tracheateu, and speciell das Araehuoideeu- und 
Myriopoden-Auge. Von. V. Graber. Archiv fur mikroskopischo Anatomic. Bd. 
xvii, Bonn., 1879, p. 58-93. (Gives a sketch on pi. vi of the brain of Julus sabu- 
losus and Lithobius forficatus.) Taf. v-vii. 
MlCHELS. Beschreibuug des nervensvstems von Oryctes nasicomis in Larveu, Pup- 
10 L 
