Literary Notices. xxxiii 



the one also which, accumulating those diverse and vague organic im- 

 pressions, which the physiologist groups under the name "kinetic", keeps 

 the animal in constant activity and readiness to respond to stimuli. 



The motive impulses, properly speiking, the external manifestations 

 of vital phenomena do not depend directly upon the diffused system. 

 Their real centre is the condensed system which must then be the true 

 organ of reactionary impulses. It isthe'centre in which are generated 

 the reflex motions ; it contains cell groups whose functions are definitely 

 specialized, and which thus form the first traces of a more advanced type 

 in which the different important manifestations of activity have become 

 localized in distinct regions. The two nervous systems are intimately 

 connected. The innumerable relations which unite them render their 

 functional agreements close and each reinforces the other. From this 

 last point of view a progressive specialization is also manifested. In fact, 

 the conduction of excitations causing the ordinary sensations which are 

 important only in the aggregate, is accomplished by means of the hidden ' 

 fibrillse which unite the condensed with the diffused system. On the 

 contrary, some ways of direct communication between the two systems 

 have been established physiologically for the special sensations before pro- 

 voking a quick response, necessary and fatal. The easy propagation of 

 sensations thus allows the corresponding motor centres to respond easily." 



The Nervous System of Crustacea. i 



Pending a more complete review of the series of which the work 

 above quoted forms a part, we present the following memoranda from 

 Edinger's "Bericht." From the body of nearly all ganglion cells there 

 arises but a single axial process ("Stamm-Fortsatz") which passes directly 

 into a commissural or axis-cylinder fibre. During its course this gives off 

 lateral branches which pass to the dotted substance of the ganglion, where 

 it divides into more or less numerous nodose branches without actual 

 anastamoses or reticulum. At the anterior end of the ventral ganglia is a 

 multipolar cell whose axial process passes into the longitudinal commissure; 

 while processes arising in part from the axial process and in part from 

 the body of the cell pass to the-dotted substance, in which they either end 

 in fine nodose branches or continue in the sheath of the ventral cord. 

 Axial processes of cells pass either cephalad or caudad and may end in the 



1. Retzils. Zur Kenntni.ss d. Nervensysteius il. I'ruiilaceen, Teipzig, 1890. 



