1/6 Journal of Comparative Neurology. 



a slight resemblance to cells artd fibers that are undoubtedly of 

 efferent nature. It may be a portion of such a one that by 

 branching among the olfactory glomerulse as indicated in the 

 figure makes a reflex course from the afferent antennal fibers to 

 the antennal muscles. Still it may be only an association fiber 

 of which there may be many in the antennal lobe, though their 

 appearance does not distinguish them as such as readily as in 

 the case of the association fibers of the rest of the brain. 

 Whatever other fibers there are that might be classed as such 

 are of small size. Some of them appear to pass into the neck 

 already spoken of as connecting the lobe to the rest of the 

 brain. 



THE root of the ANTENNO-MOTOR NERVES. 



The small internal antenno-motor nerve supplying the an- 

 tennal muscles within the head appears to be but a branch of 

 the larger one passing on to the antenna and with it has a com- 

 mon root. In sagittal sections treated by ordinary methods 

 this may be readily followed on the lower side of the antennal 

 lobe and somewhat to one side of its median line as a bundle of 

 medullated fibers that passes through the group of cells filling 

 the lower space between the oesophageal commissure and the 

 globular mass of fibrillar substance of the lobe. It penetrates 

 the fibrillar substance here and may still be followed through an 

 inward, backward, and upward course for a considerable dis- 

 tance. Gradually it decreases somewhat in size or loses its 

 fibers, and is finally untraceable. In such sections of brains 

 impregnated with bichromate of silver the fibers are frequently 

 found impregnated and then form a large bunch of branching 

 fibers spreading out in the commissure taking in the trito-cere- 

 bron and to a slight extent the ventro-cerebron. Branches also 

 pass upwards into the pro to -cerebral region. In one case of a 

 thick frontal section embracing the posterior part of the anten- 

 nal lobe and nearly all of the proto-cerebron behind its plane a 

 single fiber considerably smaller for a portion of its length can 

 be seen above the level of the lobe, as shown in Plate XVII on 

 the right where an attempt was made to reproduce it. Below 



