Kenyon, The Brain of the Bee. 135 



methods of staining. A detailed history of the matter in hand 

 is therefore needed, but since it would add too much to the 

 length of the present paper, the pretentions of which as indi- 

 cated in the title are very limited, little more than a reference 

 here and there will be given. This course is doubtless excusa- 

 ble since Retzius ( 90) has already given a summary to which the 

 reader may be referred. Three papers that have appeared since 

 the publication of this author's work may, however, be noted. 



The first of these is the paper by Saint-Remy ( 90) on the 

 brain of tracheate arthropoda. In this the author describes the 

 brains studied histologically of myriopods, chilopods, arach- 

 nids and Peripatus ; but although the work is comprehensive 

 and fills a void in our knowledge of the arthropod nervous sys- 

 tem, it is far from treating the subject with sufficient depth, a 

 deficiency mostly due to the method of staining employed. 

 The nerve cells, or cell bodies, following Dietl, he divides into 

 two groups, one composed of large cells well supplied with ex- 

 tra-nuclear protoplasm and with relatively small nuclei having 

 few chromatin elements, the other of small cells having little or 

 no extra-nuclear protoplasm and relatively large nuclei richly 

 supplied with chromatin elements and restricted to certain cere- 

 bral areas. To the latter he applies the term chromatin cells 

 in preference to the ganglionary nuclei of Dietl and others. 



Two small nerves that he describes for the myriopods may 

 be passed by with the remark that one, namely the nerve of 

 Tomosvary appears to have no homologue in the hexapods un- 

 less it be the small nerve mentioned by Newton ( 79) as arising 

 from the front of the brain of the cockroach and terminating in 

 a small organ near the base of the antenna. The other, or 

 tegumentary, nerve may be the homologue of the tegumentary 

 nerve described by Viallanes ( gg) for the grasshoppers and con- 

 sequently, as will be shown in subsequent pages, the homo- 

 logue of the salivary nerve that I have traced out in the bee. 



The most interesting discovery recorded in the paper is 

 that of structures found in the brain of Saitigra that he de- 

 scribes as mushroom bodies. The term he bases upon their 

 form and not upon an idea of their being the homologues of the 



