178 JoURNAL OF COMPARATIVE NEUROLOGY. 
3. Ramus Lateralis Vagi : : 3 - re 
IV. The Sympathetic Nervous System . : > MT 
ParT II, THE CUTANEOUS SENSE ORGANS : : 5 214 
I. Organs of the Communis System 4 c : 7, eens 
II, Organs of the Acustico-Materalis System. 5 215 
The Lateral Line Canals and their Sense Oiganst in A. melas 216 
2. Comparison of Lateral Line Canals of other Siluroids 223 
Review of the Literature . é ; : Bie ay Pe: 
Ameiurus melas, Jordan and Cope : : : 226 
Ameiurus nebulosus, LeSueur z > : Ree 
Ameiurus catus, L. : ; : : : 229 
Leptops olivaris, Raf. : . - : 2 229 
Ictalurus punctatus, Raf. : 5 ° . 230 
Noturus flavus, Raf. : - 5 : <1 20 
The Post-temporal Bone of Menidia ; - 231 
3. The Pit organs ‘ : “ . : Sy. ete 
SUMMARY AND CONCLUSIONS : : : : : 237 
LITERATURE . . . ; . ; . - 242 
DESCRIPTION OF FIGURES. : ; : : = 245 
INTRODUCTION. 
Among the multitudes of interesting problems which are 
suggested by the study of the literature upon the fishes, few 
are of greater interest or of more far reaching significance than 
those centering about the diverse kinds of cutaneous sense 
organs among these types. A great step in advance was 
marked by MERKEL’s discovery that these sense organs can be 
referred to two chief types, each with many varieties: viz. (1) 
the terminal buds, ‘‘End-knospen,”’ similar in structure to the 
taste buds of the buccal cavity, and (2) the neuromasts, or 
organs of the lateral line system, ‘‘Nervenhigel,”’ characterized 
by the presence of pear cells or specific sensory cells shorter 
than the others of the sensory epithelium and resembling in 
structure the hair cells of the organs of the internal ear. 
Several of the recent students of nerve components among 
the Ichthyopsida have brought forth more or less convincing 
evidence that these two structural types can likewise be distin- 
guished in their innervation, the terminal buds being supplied 
by the communis system of nerves and the neuromasts by the 
-acustico-lateralis system. The reader is referred to the works 
_of Strone, ALLIs, Kincspury, CoLe, JOHNSTON, Houser and 
