Nachdruck verboten. 

 Uebersetzungsrecht vorbehalten. 



The finer Structure of the Nerve Cells of Invertebrates. 



I. Gastropoda. 



By 



Charles F. W. McClure, 



Assistant Professor at Princeton University, New Jersey, U. S. A. 



With Plates 2 and 3. 



The question concerning the finer anatomy of the nerve cells of 

 Invertebrates, although in the past somewhat extensively studied, has 

 not in the present era, since the development of the modern methods 

 of technique, received the attention which it deserves. It is for this 

 reason, as well as because certain discrepancies of opinion exist con- 

 cerning the results obtained by the use of the more modern methods, 

 that the writer feels justified in entering this field. 



At the present writing, although some differences of opinion may 

 exist concerning the more detailed structure of the nerve cells of 

 Vertebrates, all are agreed I think, as to the division of the contents 

 of most of these cells, into two general classes of elements, which by 

 virtue of their relative affinity for certain dyes, notably methylen 

 blue, are roughly spoken of as stainable and unstainable elements. 

 The former of the two classes of elements (chromatic or chromophilous) 

 includes what the Germans describe under the names of "Körnchen", 

 "Körner" and "Schollen". 



It is also known that the size, form and arrangement of these 

 chromatic or chromophilous elements may be exceedingly variable in 

 different cells; and that this variability, especially as to the manner 

 in which they are arranged in the cell, has formed the basis, by means 

 of which NissL (28) has temporarily classified the nerve cells of Verte- 

 brates, into four principal types. 



