The Nervous System of Chelifer 
WILLIAM A. HILTON 
There has been very little published on the nervous system and 
sense organs of arachnids and almost nothing on pseudoscor- 
pions. There are, however, a large number of papers dealing 
with the classification of the latter and a few anatomical papers, 
such as those of Bertkau ’87, Croneberg ’88 and Supino ’99. I 
have not seen these three works. There are no references given 
to them by the recent investigators of the arachnid nervous 
system. 
Some of the early work dealing with the central nervous 
system of Arachnida we find recorded in the papers of Tre- 
viranus *16 and ’32, Brandt ’40, Grube ’42. These authors 
deseribe and figure in a general way the external form of the 
nervous system of spiders. A more recent paper is that of 
Schimkewitch ’84. This author considered the brain of Epeira 
and determined two regions in the supraesophageal ganglion, an 
optie region connected with the optic nerves, and a mandibular 
connected with nerves to the mandibles. Saint Remy ’90 has an 
extensive contribution to the nervous system of spiders. He 
considers especially the brain in which he names the two chief 
regions, the ocular and the rostro-mandibular because the so- 
called mandibular nerve supplies the upper parts of the head as 
well as the chelicere. Many details of structure are given for 
the genera, Lycosa, Thomisus, Epeira, Tegenaria, Drassus, 
Segestria, Pholcus and Eresus. Something to correspond to 
mushroom bodies of insects is recognized in the posterior strat- 
ified body located in the uppermost part of the head in a lobe at 
the posterior dorsal region of the brain. 
The paper of Lambert ’09 is chiefly an embryological study 
of parts of the nervous system of Epeira. He figures the adult 
brain of Argiope with cheliceral and mandibular branches 
coming off from the subesophageal ganglion, or at least farther 
from the optic mass than they are usually described and figured. 
More recent papers on the nervous system of spiders are those 
