318 E. T, NEWTON. 



1834), these stomato-gastric ganglia are connected Avith the 

 brain; and Loydig states that the same thing occurs in 

 Dijtiscus. Flogei states, on thp authority of Kupffer, that this 

 connection is also found in Blatta ; and, on trtt~gai}]f.fVuthoritv,- 

 they are said to send fibres to the salivary glands. 



Internal Structure of the Brain. 



The internal structures of the brain, which are described 

 in the following pages, have been worked out chiefly by 

 means of series of sections, cut in definite directions, but 

 this has to some extent been supplemented by dissections. 

 Brains hardened in osmic acid, after the manner adopted by 

 Dietl, were found to be most satisfactory, but others hardened 

 in alcohol and stained Avith carmine were very useful for 

 comparison. The most instructive sections Avere those 

 which have been called " frontal sections ;" that is, cut 

 as nearly as possible parallel Avith the front surface of the 

 brain ; the first section including portions of both the hemi- 

 spheres and the antennary lobes. One brain, Avhich had been 

 hardened in osmic acid, Avas cut in this Avay into thirty- 

 four sections, each about the TW"oth of an inch in thickness, 

 and from these I was enabled to construct the model 

 already alluded to. From this series of section those have 

 been selected for illustration Avhich it Avas thought Avould 

 best explain the various structures, and Avill be found repre- 

 sented on Plate XVI. 



Some of the internal parts of the insects^ brain liaA-e 

 received different names from different authors, and hence 

 several names have in some cases been given to one and the 

 same part. Dr. Flogei, evidently seeing the difficulty likely 

 to arise from this loose nomenclature, has suggested certain 

 terms Avhich might be used by future Avriters on the 

 subject. Most of these terms-Avould, no doubt, have been at 

 once adopted ; but, unfortunately, they are given in German, 

 and it would be necessary for other than German Avriters 

 to render them in equivalent terms of their own language. 

 I Avould suggest, therefore, that Ave noAV, once for all, 

 latinise these terms, and thus obviate this difficulty also. 

 The mass of nervous matter found at tbe loAver part 

 in each hemisphere (marked t in the accompanying figures), 

 and called by Flogei the '* Balke7i," may be called the 

 trahecula. That peculiar mass of nervous tissue passing 

 off from the trahecula, and ending abruptly on the front 

 of the brain, termed by the same author '' Vorderhorn,''^ 

 Avould then become the anterior cornw, but this name 



