[ 115 ] 



V. Observations on the St7'nctiire and Moiyhology of the Cranial Nerves and Lateral 

 Sense Organs of Fishes ; tcith special reference to the Genus Gadiis. By Frank J, 

 CoIj'e, Demonstrator of Zoology, University College, Liverpool. [Communicated by 

 Prof. W. A. Herdman, D.Sc, F.B.S.) 



AUG 20 >899 



(Plates 21-23.) 



Read 3rd March, 1898. 



Contents. 



Page 



A. Introduction 116 



B. Historical 117 



C. Sensory Canals in General 120 



Conclusions 120 



D. Sensory Canals of Gadus morrhtia 122 



(1) Supra-orbital Canal 122 



(2) Lifra-orbital Canal 123 



(3) Hyomandibular Canal 126 



(4) Lateralis Canal 127 



Supra-temporal Portion 127 



Lateral or Body Portion 127 



E. Gadus morrlMa and Gadiis virens compared . . 129 



F. The Sense Organs on the Lateral line Canals . . 129 



G. Other Sense Organs belonging to the Lateral 



line System 131 



H. Eelation of the Sensory Canals to the SkuU . . 131 



Conclusions 132 



I. The Trigemino-facial Ganglionic Complex .... 133 



J. Morphology of the Facial Ganglion 136 



(1) Conclusions 142 



(2) Typical Branchial Nerve 144 



(3) Facial Nerve of Man 144 



K. Morphology of Jacobson's Anastomosis 145 



Conclusions 147 



L. Metamerism of the Lateral line System .... 148 



(1 ) Conclusions 152 



(2) Value of the Lateral line Nerves 154 



M. Innervation of the Sensory Canals in Gadus . . 156 



(1) Supra-orbital Canal 156 



Superficial Ophthalmic Trunk 156 



SECOND SERIES. — ZOOLOGY, VOL. VII. 



Page 



(2) Infra-orbital Canal 158 



Buccal Trunk 158 



(3) Hyomandibular Canal 161 



Hj'omandibular Trunk 161 



(4) Lateralis Canal 164 



Laterahs Trunk 164 



N. Structure and Morphology of the R. lateralis 



accessorius (" trigemini '") 166 



(1) Condition in Gadus 17.5 



(2) General Conclusions 177 



0. Morphological Value of the Lateralis Nerve of 



Petromyzon . 178 



Conclusions 179 



P. Gadus compared with other forms 179 



Amia 181 



Q. The Lateral Sense Organs of Vertebrates and 



Invertebrates 185 



Conclusions 186 



Iv. The Phylogeuy of the Sensory Canals 187 



Conclusions 192 



S. The Lateral Sense Organs and the Auditory 



Organ 194 



Conclusions 197 



T. Special Considerations 199 



(1) Friant (1879) 199 



(2) Morphology of the Facial Nerve of 



Fishes 200 



Summary 203 



Bibliography 20U 



17 



