CONTENTS xi 



CHAPTER XXVI. 



The Elasmobranch Fishes ; British Dog-fishes, Rays and Skates j 

 External Features of Scyllium canicula ; Skin, Denticles, 

 and Teeth; Myotomes; Skeleton; Axial Skeleton, Vertebral 

 Column, and Cranium ; Jaws ; Branchial Skeleton ; Pectoral 

 Fins and Pelvic Fins ; Dorsal and Ventral Fins ; Coelom ; 

 Head Cavities ; Alimentary Canal ; Spiracles and Gill-slits ; 

 Extra- Branchial Cartilages ; Heart ; Afferent and Efferent 

 Branchial Arteries ; Dorsal Aorta and its Branches ; Venous 

 System ; Renal- Portal System ; Hepatic Portal System ; 

 Pronephros, Meson ephros, and Metanephros ; Reproductive 

 Organs ; Wolffian and Miilleriari Ducts ; Brain ; Cranial 

 Nerves ; Occipital Nerves ; Sympathetic Nerves ; Olfactory 

 Organs ; Eyes ; Auditory Organs ; Primitive Characters of 

 Dogfish ....... 203-246 



CHAPTER XXVII. 



The Development of the Frog ; the Tadpole and its Meta- 

 morphosis ; Closure of the Blastopore ; Internal Changes 

 during Closure of the Blastopore ; Rotation of the Egg ; 

 Neural Folds ; Neurenteric Canal ; Formation of Mesoblast ; 

 Notochord ; Mesoblastic Somites ; Liver, Pancreas and 

 Cloacal Bladder ; Gill-Slits ; External Gills ; Lungs ; 

 Myotomes ; Genital Ridges ; Development of Vertebrae ; 

 Development of Skull ; Formation of Heart and Peri- 

 cardium ; Development of Venous and Arterial Systems ; 

 Pronephros and Mesonephros ; Segmental Duct and 

 Oviducts ; Development of Brain ; Olfactory Organs ; 

 Auditory Organs ; Eye ; Ontogeny and Phylogeny . 247-283 



CHAPTER XXVIII. 



The Mammalia ; Hair ; Sweat Glands ; Mammary Glands ; 

 External Ear ; Perinreum ; Hard Palate ; Teeth ; 

 Alimentary Canal ; Vertebral Column ; Skull ; Auditory 

 Ossicles ; Sternum ; Shoulder Girdle and Pelvic Girdle ; 

 Limbs ; Diaphragm ; Heart ; Arterial Arches ; Venous 

 ' System ; Red Corpuscles ; Brain ; Auditory Organ ; 

 Cochlea ; Urogenital System ; Placentation ; Blastocyst ; 

 Trophoblast; Trager ; Formation of Embryo ; Amnion ; 

 Allantois ; Allantoidean Placenta ; Omphaloidean Placenta ; 

 Decidua . . . 284-307 



CONCLUSION ,..... 308-311 

 INDEX ,,,... 313-321 



