xviii ILLUSTRATIONS. 



172. Common Calamary (Loligo vulgaris) . 295 



173. Water-snails (Limncddce) . . 298 



174. Grey Field-slug (Agriolimax agrestis) 300 



175. Testacella (T. haliotidea) . ■ 301 



176. Garden Snail (Helix aspersn) . 302 



177. Structure of a Tunicate . . 308 



178. Development of a Tunicate . 309 



179. The Lancelet (ili«/)/iJoa:MS Zamoeo^aii/s) . . 309 



180. Diagrammatic Sections of an Invertebrate and Vertebrate . 311 



181. Slieleton of Horse .... .316 



182. Lumbar Vertebra . . . 317 



183. Axis ...... .318 



184. Atlas ... . . .318 



185. Skull of the Horse . . . .319 



186. Diagram of the Relations of the Principal Bones of the Jlam- 



malian Skull . . 320 



187. Fore and Hind Leg of Horse 322 



188. Pelvic Arch . . ... 325 



189. General View of the Intestines of the Horse 328 



190. Diagram of Alimentary Canal . . . 329 



191. Theoretical, Longitudinal, and Median Section of Abdominal 



Cavity, to show Peritoneum . 333 



192. Median Longitudinal Section of Head and Upper Part of Neck 



of Horse . . . . . 334 



193. Uro-Genital Apparatus of Male, with Arteries . . 338 



194. Generative Organs of the Mare . 340 



195. Diagram of the Circulation of the Blood 342 



196. Brain of Horse (dorsal view) 346 



197. Brain of Horse (ventral view) . . 347 



198. The Perch (Pc)r.(/i(ri,«i7 is) 352 



199. Diagram of the Circulation in Fishes . 353 



200. Development of the Frog . . . 356 



201. Male Crested Newt (rWtoTi cris(a(Ms) . S.'^S 



202. Diagram of the Circulation in Reptiles . 361 



203. Pleurodont and Acrodont Dentition . 362 



204. Head of Reptiles . 362 



205. 'SimA-yiorra (Anguis friigilis) 364 



206. Feather of Bird . . .366 



