STUDIES ON THE NERVOUS SYSTEM OF CRUSTACEA. 483 
Studies on the Nervous System of Crustacea. 
By 
Edgar J. Allen, B.Sc.Lond. 
With Plates 37 and 38. 
II.—The Stomatogastric System of Astacus and Homarus. 
III,—On the Beading of Nerve-fibres and on End Swellings, 
II. 
Wirn a view to making myself acquainted with the use of 
Ehrlich’s methylene blue method, in order to study the struc- 
ture of the nervous system of the larve and embryos of Decapod 
Crustacea, I made preliminary trials upon the stomatogastric 
nervous system of Astacus. As several points of interest 
appeared, I carried the observations further than I had intended, 
and I now propose to give some account of them, especially as 
I am able to supplement them in one or two particulars by 
observations which I have made during my later work on the 
embryos of Homarus. 
The greater portion of the research recorded here was carried 
out in the zoological laboratory at University College, and my 
thanks are due to Professor Weldon for the help and advice 
which he has given. 
Mertnuop.—My attention was chiefly directed to the study of 
that portion of the stomatogastric system which puts it into 
communication with the central nervous system of the animal. 
The following mode of procedure was adopted :—The animal, 
after being killed with chloroform, was opened from the dorsal 
VOL. 386, PART 4,—NEW SER. KK 
