Herkigk, Mor-phology of Brain of Bony Fislics. 243 



The cat-fish group presents more remarkable variations, 

 which have been explained in detail by C. Judson Herrick. 



In the drum the most remarkable peculiarity of the mid- 

 region of the brain is its relative shortness; the cerebellum is 

 crowded far dorsad and lies perched, as it were, between the 

 trigeminal lobes and the vertically elongate optic lobes. The 

 great dorsal elevation and corresponding shortening of the 

 optic lobes could not fail to exert a greatly modifying influ- 

 ence on the volvula, which in these fishes is very large. The 

 result is seen in a curious multiple folding of the dorsal 

 lamina in the frontal plane; so that successive lobes appear 

 in transverse section. The remainder of the cerebellum 

 shows no other eftect of the compression than that exhibited 

 in its position and a slight cephalo-dorsal protuberance. 



The examples cited are sufficient to show that the most 

 divergent types may easily be reduced to a single funda- 

 mental form. 



The cranial nerves have not been carefully studied in this 

 connection, because of an exegency of publication, nor has 

 there been opportunity to compare the papers of Prof. 

 Wright on the cranial nerves of the cat fish. In the cat 

 fish the exaggerated development of the trigeminal system is 

 well illustrated in the earlier installment of this series, by C. 

 Judson Herrick. 



In the drum [Haploidonotus) the following relations 

 prevail: The vagus consists of two nearly equal branches, one 

 of which springs from the caudal portion of the vagal tuber- 

 osity, while the other is derived from the extreme cephalic 

 portion, and both are apparently derived from nearly the 

 same dorso-ventral level. The two branches remain distinct 

 for some distance, so that the cephalad root has an in- 

 dependent course, nearly twice as long as that of its fellow. 

 At their union a more or less distinct ganglion is developed. 

 From the latter the small nerve of the lateral line arises. A 

 visceral branch and a branch probably supplying the pectoral 

 fin-muscles follow, and then five branches to the gills, the 



