Circulatory System of Elasmobranchs in General — Continued page 



Arterial supply to trunk 186 



Dorsal aorta 186 



Unpaired arteries 186 



Coeliac axis and its branches 186 



Superior mesenteric artery 188 



Inferior mesenteric artery 190 



Paired branches of aorta 191 



Subclavians and iliacs 191 



Segmentals 192 



Caudal segmentals 193 



Bibliography 195 



VIII. CIRCULATORY SYSTEM {Continued) 



Circulatory System of Heptanchus maculatus 198 



Veins * 198 



Veins of head 198 



Veins of tail 199 



Veins from kidney or mesonephros 200 



Veins from digestive tract . • 200 



Veins of body wall 202 



Veins of skin 202 



Circulatory System of Elasmobranchs in General 204 



Veins - 204 



Anterior cardinal sj'stem 204 



Renal portal system 208 



Posterior cardinal veins 209 



Hepatic portal system 210 



Development of hepatic portal system 212 



Lateral abdominal system of veins 213 



Veins of heart 215 



Cutaneous sj'stem of veins 216 



Nature of cutaneous system of vessels 217 



Lymphatic vessels 218 



Bibliograph}' 219 



IX. NERVOUS SYSTEM 



Nervous System of Heptanchus maculatus 221 



Central nervous system 221 



Brain 221 



Spinal cord 222 



Peripheral nervous system 222 



Cranial nerves 223 



Occipitospinal nerves 227 



Spinal nerves : 227 



Nervous System of Elasmobranchs in General 229 



Development of central nervous system 230 



Gross form of brain 230 



Internal view of brain 235 



Spinal cord 237 



Peripheral nervous system 238 



Cranial nerves 238 



Spinal nerves 246 



SjTnpathetic or autonomic nervous system 247 



Bibliography 249 



[X] 



