Cardium or Cockle 230 166. Foot of Cockle 231 167. Section of shell of Pinna transversely to the direction of its prisms 233 168. Membranous basis of the shell of the Pinna 233 169. Section of nacreous lining of the shell of Avicula margaritacea (pearl oyster) 234 170. Tongue of Helix aspersa 237 171. Palate of Trochus zizyphinus 237 172. Granulated Trochus 238 173. Tongue of Limpet 238 174. Whelk 240 175. The Crowned Eolis 240 176. Tongue-teeth of Eolis coronata 241 177. Hyalæa and Clio 243 178. Clione borealis 243 179. Cuttle Fish 245 180. Arm of Octopus 247 Footnote A: From Dr. Ernst Haeckel’s ‘Radiolarien.’ Footnote B: From Voght’s ‘Syphonophores de la Mer de Nice’. MOLECULAR AND MICROSCOPIC SCIENCE. PART III. ANIMAL ORGANISMS. SECTION I. FUNCTIONS OF THE ANIMAL FRAME. ALTHOUGH animal life is only known to us as a manifestation of divine power not to be explained, yet the various phases of life, growth, and structure in animals, from the microscopic Monad to Man, are legitimate subjects of physical inquiry, being totally independent of those high moral and religious sentiments which are peculiar to Man alone. The same simple elements chemically combined in definite but different proportions form the base of animal as well as of vegetable life. But besides the elementary gases and carbon, many substances, simple and compound, are found in the animal frame; the phosphate and carbonate of lime, iron which colours the blood, and common salt which, with the exception of water, is the only article of food we use in a mineral state. Animals derive their nourishment, both directly and indirectly, from vegetables. Their incapacity to change inert into living matter is one of the most characteristic distinctions between the animal and vegetable kingdoms.