LIST OF ILLUSTRATIONS. 



XIX 



Octopus carena, . . . 303 

 Paper Nautilus, . . . 305 

 Diagram of Belemnite, . 306 

 Pearly Nautilus, . . . 308 

 Diagram of the Siphuncle 

 and Septa in the Shells 

 of various Tetrabranchi- 

 ate Cephalapods, . .310 

 Orthoceras explorator^ . 311 

 Shells of Secondary Ce- 



phalopods, .... 314 

 Transverse Sections of the 

 body of an invertebrate 

 and a vertebrate animal, 324 

 Embryology ofVertebrata, 325 

 Lumbar Vertebra of Whale, 

 and diagram of thoracic 

 vertebra, .... 328 

 Skeleton of the Beaver, 329 

 Pectoral limb of Chim- 

 panzee, 331 



Pelvic Limb of Chimpan- 

 zee, 332 



Diagram of the digestive 



system of a Mammal, . 333 

 Blood-corpuscles of Ver- 



tebrata, 334 



Diagram of the circula- 

 tion of a Mammal, . . 335 

 Scales of Fishes, . . . 340 

 Skeleton of the Common 



Perch 341 



Skull of the Cod, . . .343 

 Os hyoides and branchial 



arches of the Perch, . 345 

 Pectoral limbs of Fishes, 346 

 Outline of Percagranu- 



lata, 348 



Homocercal and hetero- 



cercal tails, .... 349 

 Diagram of the circula- 

 tion of a Fish, . . .350 

 Diagram of the Lancelet, 354 



Lamprey, 355 



Heart of Teleostean and 



Ganoid Fishes, . . . 359 

 Gymnotus electricus, . . 360 

 Rhombus punctatus, . . 362 

 Ostracion cornutus, . . 364 

 Polypterus and Osteolepis, 367 

 Cephalaspis Lyellii, . . 369 

 Coccosteus and Pterichthys, 369 

 Head of Piked Dog-fish, 371 

 Carcharias and Chimera, 372 

 Raia marginata, , . .374 

 Lepidosiren annectens, . 376 



