CONTENTS 



PAGE 



Sub-Grade 1. CHONDRICHTHYES . 118 



Placoid scale, 119 ; Dentine, 119 ; Ceratotrichia, 122 ; Gill slits 

 and rays, 123 ; Classification, 123. 



DIAGRAM OF PHYLOGENY, 124 

 Sub-Class 1. ELASMOBRANCHII . . 125 



Nostrils, 125; Lateral line, 125; Brain, 126; Pectoral fin- 

 skeleton and archipterygium, 127 ; Pelvic fin, 128; Claspers, 

 129; Urinogenitals, 131 ; Viviparity, 134. 



Order 1. SELAOHII . .135 



Centra, 135 ; Skeleton, 137 



Group 1. 



Sub-Order 1. NOTIDANI . 139 



Fain. 1. Chlamydoselachidae, 142 ; Fam. 2. Notidanidae, 143. 



Group 2. 



Division A . . 143 



Sub-Order 1. HETERODONTI .... 143 



Fam. 1. Cestraciontidae, 145; Fain. 2. Cochliodontidae, 146; 

 Fam. 3. Edestidae, 147. 



Division B .148 



Subdivision 1. 



Sub-Order SCYLLIOIDEI . . 148 



Fam. 1. Scylliidae, 149; Fam. 2. Lamnidae, 149; 

 Fam. 3. Carchariidae, 150. 



Subdivision 2. 



Sub-Order 1. SQUALIFORMES . . 151 



Fam. 1. Spinacidae, 151 ; Fam. 2. Pristiophoridae, 152. 



Sub-Order 2. RAJIFORMES . . 153 



Tribe 1, 155. 



Fam. Squatinidae, 156. 



Tribe 2, 158. 



Group A. Rhitioraji, 159. 



Fam. 1. Rhinobatidae, 159 ; Fam. 2. Pristidae, 

 160 ; Fam. 3. Rajidae, 160. 



Group B, Torpedinoidei, 161. 

 Fam. Torpedinidae, 161. 



Group C. Centrobatoidei, 163. 



Fam. 1. Trygonidae, 164 ; Fam. 2. Pfcychodontidae, 

 165; Fam. 3. Myliobatidae, 165 ; Fam. 4. Psammo- 

 dontidae, 167. 



INCERTAE SEDIS. Fam. 5. Petalodontidae, 167. 



