40 



Bulletin of Laboratories of Denison University, [voi.xiii 



usually calls forth a movement of the whole body toward the 

 food object, while this is unnecessary in the case of a gustatory 

 stimulus received within the mouth. This is the probable rea- 

 son for the differentiation of a special center in the medulla ob- 

 longata for the reception of the facial root of the communis sys- 

 tem, the lobus facialis, or " tuberculum impar, " in those species 

 which possess large numbers of terminal buds in the outer skin. 



Fig. J. Two views of the brain of the buffalo fish, Carpiodcs vclifcr (Raf.), 

 (i) from above, (2) from the right side. X 2. After C. L. Hkrrick. 



The vagal lobes (A. 7'^''.) are relatively larger than in the carp and, with the 

 overhanging cerebellum, completely conceal the facial lobe. In the lower figure 

 the branches of the trigemino-facial root complex are marked Vi.d., J^i.i'., V2, 

 VII, and the root of the auditory nerve VIII. Between, the latter and the 

 caudal tip of the optic lobe is a well-defined protulierance ventrally of the cerebel- 

 lum. This is the lateral portion of the superior secondary gustatory nucleus 

 {Rindenknoten, Mayser). Caudad of this, immediately dorsally of the VIII root, 

 is the small lobus lineae lateralis (Johnston) from which the tuberculum acusti- 

 cum and cerebellar crest extend caudad beneath the vagal lobe. In the upper 

 figure, the median shaded part of the roof of the optocoele is membranous, the 

 optic lobes being widely divaricated tjy the enormous valvula cerebolli. In both 

 figures the membranous roof of the fore-brain is dissected away to show the 

 lobules of the basal ganglia, and the olfactory Inilbs are cut away. 



With the exception just noted, it is probably safe to as- 

 sume that there will be found broad lines of similarity between 



