Produced by Sue Asscher asschersbigpondcomTHE EVOLUTION OF MANA POPULAR SCIENTIFIC STUDYBYERNST HAECKELVOLUME 2HUMAN STEMHISTORY OR PHYLOGENYTRANSLATED FROM THE FIFTH ENLARGED EDITION BY JOSEPH MCCABEISSUED FOR THE RATIONALIST PRESS ASSOCIATION LIMITEDWATTS  CO17 JOHNSONS COURT FLEET STREET LONDON EC1911CONTENTS OF VOLUME 2LIST OF ILLUSTRATIONSINDEXCHAPTER 216 STRUCTURE OF THE LANCELET AND THE SEASQUIRTCHAPTER 217 EMBRYOLOGY OF THE LANCELET AND THE SEASQUIRTCHAPTER 218 DURATION OF THE HISTORY OF OUR STEMCHAPTER 219 OUR PROTIST ANCESTORSCHAPTER 220 OUR WORMLIKE ANCESTORSCHAPTER 221 OUR FISHLIKE ANCESTORSCHAPTER 222 OUR FIVETOED ANCESTORSCHAPTER 223 OUR APE ANCESTORSCHAPTER 224 EVOLUTION OF THE NERVOUS SYSTEMCHAPTER 225 EVOLUTION OF THE SENSEORGANSCHAPTER 226 EVOLUTION OF THE ORGANS OF MOVEMENTCHAPTER 227 EVOLUTION OF THE ALIMENTARY SYSTEMCHAPTER 228 EVOLUTION OF THE VASCULAR SYSTEMCHAPTER 229 EVOLUTION OF THE SEXUAL ORGANSCHAPTER 230 RESULTS OF ANTHROPOGENYLIST OF ILLUSTRATIONSFIGURE 2210 THE LANCELETFIGURE 2211 SECTION OF THE HEAD OF THE LANCELETFIGURE 2212 SECTION OF AN AMPHIOXUSLARVAFIGURE 2213 DIAGRAM OF PRECEDINGFIGURE 2214 SECTION OF A YOUNG AMPHIOXUSFIGURE 2215 DIAGRAM OF A YOUNG AMPHIOXUSFIGURE 2216 TRANSVERSE SECTION OF LANCELETFIGURE 2217 SECTION THROUGH THE MIDDLE OF THE LANCELETFIGURE 2218 SECTION OF A PRIMITIVEFISH EMBRYOFIGURE 2219 SECTION OF THE HEAD OF THE LANCELETFIGURES 2220 AND 2221 ORGANISATION OF AN ASCIDIAFIGURES 2222 TO 2224 SECTIONS OF YOUNG AMPHIOXUSLARVAEFIGURE 2225 AN APPENDICARIAFIGURE 2226 Chroococcus minorFIGURE 2227 Aphanocapsa primordialisFIGURE 2228 PROTAMOEBAFIGURE 2229 ORIGINAL OVUMCLEAVAGEFIGURE 2230 MORULAFIGURES 2231 AND 2232 Magosphaera planulaFIGURE 2233 MODERN GASTRAEADSFIGURES 2234 AND 2235 Prophysema primordialeFIGURES 2236 AND 2237 Ascula of GastrophysemaFIGURE 2238 OlynthusFIGURE 2239 Aphanostomum LangiiFIGURES 2240 AND 2241 A TURBELLARIANFIGURES 2242 AND 2243 ChaetonotusFIGURE 2244 A NEMERTINE WORMFIGURE 2245 AN ENTEROPNEUSTFIGURE 2246 SECTION OF THE BRANCHIAL GUTFIGURE 2247 THE MARINE LAMPREYFIGURE 2248 FOSSIL PRIMITIVE FISHFIGURE 2249 EMBRYO OF A SHARKFIGURE 2250 MANEATING SHARKFIGURE 2251 FOSSIL ANGELSHARKFIGURE 2252 TOOTH OF A GIGANTIC SHARKFIGURES 2253 TO 2255 CROSSOPTERYGIIFIGURE 2256 FOSSIL DIPNEUSTFIGURE 2257 THE AUSTRALIAN DIPNEUSTFIGURES 2258 AND 2259 YOUNG CERATODUSFIGURE 2260 FOSSIL AMPHIBIANFIGURE 2261 LARVA OF THE SPOTTED SALAMANDERFIGURE 2262 LARVA OF COMMON FROGFIGURE 2263 FOSSIL MAILED AMPHIBIANFIGURE 2264 THE NEW ZEALAND LIZARDFIGURE 2265 Homoeosaurus pulchellusFIGURE 2266 SKULL OF A PERMIAN LIZARDFIGURE 2267 SKULL OF A THEROMORPHUMFIGURE 2268 LOWER JAW OF A PRIMITIVE MAMMALFIGURES 2269 AND 2270 THE ORNITHORHYNCUSFIGURE 2271 LOWER JAW OF A PROMAMMALFIGURE 2272 THE CRABEATING OPOSSUMFIGURE 2273 FOETAL MEMBRANES OF THE HUMAN EMBRYOFIGURE 2274 SKULL OF A FOSSIL LEMURFIGURE 2275 THE SLENDER LORIFIGURE 2276 THE WHITENOSED APEFIGURE 2277 THE DRILLBABOONFIGURES 2278 TO 2282 SKELETONS OF MAN AND THE ANTHROPOID APESFIGURE 2283 SKULL OF THE JAVA APEMANFIGURE 2284 SECTION OF THE HUMAN SKINFIGURE 2285 EPIDERMIC CELLSFIGURE 2286 RUDIMENTARY LACHRYMAL GLANDSFIGURE 2287 THE FEMALE BREASTFIGURE 2288 MAMMARY GLAND OF A NEWBORN INFANTFIGURE 2289 EMBRYO OF A BEARFIGURE 2290 HUMAN EMBRYOFIGURE 2291 CENTRAL MARROW OF A HUMAN EMBRYOFIGURES 2292 AND 2293 THE HUMAN BRAINFIGURES 2294 TO 2296 CENTRAL MARROW OF HUMAN EMBRYOFIGURE 2297 HEAD OF A CHICK EMBRYOFIGURE 2298 BRAIN OF THREE CRANIOTE EMBRYOSFIGURE 2299 BRAIN OF A SHARKFIGURE 2300 BRAIN AND SPINAL CORD OF A FROGFIGURE 2301 BRAIN OF AN OXEMBRYOFIGURES 2302 AND 2303 BRAIN OF A HUMAN EMBRYOFIGURE 2304 BRAIN OF THE RABBITFIGURE 2305 HEAD OF A SHARKFIGURES 2306 TO 2310 HEADS OF CHICKEMBRYOSFIGURE 2311 SECTION OF MOUTH OF HUMAN EMBRYOFIGURE 2312 DIAGRAM OF MOUTHNOSE CAVITYFIGURES 2313 AND 2314 HEADS OF HUMAN EMBRYOSFIGURES 2315 AND 2316 FACE OF HUMAN EMBRYOFIGURE 2317 THE HUMAN EYEFIGURE 2318 EYE OF THE CHICK EMBRYOFIGURE 2319 SECTION OF EYE OF A HUMAN EMBRYOFIGURE 2320 THE HUMAN EARFIGURE 2321 THE BONY LABYRINTHFIGURE 2322 DEVELOPMENT OF THE LABYRINTHFIGURE 2323 PRIMITIVE SKULL OF HUMAN EMBRYOFIGURE 2324 RUDIMENTARY MUSCLES OF THE EARFIGURES 2325 AND 2326 THE HUMAN SKELETONFIGURE 2327 THE HUMAN VERTEBRAL COLUMNFIGURE 2328 PIECE OF THE DORSAL CORDFIGURES 2329 AND 2330 DORSAL VERTEBRAEFIGURE 2331 INTERVERTEBRAL DISKFIGURE 2332 HUMAN SKULLFIGURE 2333 SKULL OF NEWBORN CHILDFIGURE 2334 HEADSKELETON OF A PRIMITIVE FISHFIGURE 2335 SKULLS OF NINE PRIMATESFIGURES 2336 TO 2338 EVOLUTION OF THE FINFIGURE 2339 SKELETON OF THE FORELEG OF AN AMPHIBIANFIGURE 2340 SKELETON OF GORILLAS HANDFIGURE 2341 SKELETON OF HUMAN HANDFIGURE 2342 SKELETON OF HAND OF SIX MAMMALSFIGURES 2343 TO 2345 ARM AND HAND OF THREE ANTHROPOIDSFIGURE 2346 SECTION OF FISHS TAILFIGURE 2347 HUMAN SKELETONFIGURE 2348 SKELETON OF THE GIANT GORILLAFIGURE 2349 THE HUMAN STOMACHFIGURE 2350 SECTION OF THE HEAD OF A RABBITEMBRYOFIGURE 2351 SHARKS TEETHFIGURE 2352 GUT OF A HUMAN EMBRYOFIGURES 2353 AND 2354 GUT OF A DOG EMBRYOFIGURES 2355 AND 2356 SECTIONS OF HEAD OF LAMPREYFIGURE 2357 VISCERA OF A HUMAN EMBRYOFIGURE 2358 RED BLOODCELLSFIGURE 2359 VASCULAR TISSUEFIGURE 2360 SECTION OF TRUNK OF A CHICKEMBRYOFIGURE 2361 MEROCYTESFIGURE 2362 VASCULAR SYSTEM OF AN ANNELIDFIGURE 2363 HEAD OF A FISHEMBRYOFIGURES 2364 TO 2370 THE FIVE ARTERIAL ARCHESFIGURES 2371 AND 2372 HEART OF A RABBITEMBRYOFIGURES 2373 AND 2374 HEART OF A DOGEMBRYOFIGURES 2375 TO 2377 HEART OF A HUMAN EMBRYOFIGURE 2378 HEART OF ADULT MANFIGURE 2379 SECTION OF HEAD OF A CHICKEMBRYOFIGURE 2380 SECTION OF A HUMAN EMBRYOFIGURES 2381 AND 2382 SECTIONS OF A CHICKEMBRYOFIGURE 2383 EMBRYOS OF SAGITTAFIGURE 2384 KIDNEYS OF BDELLOSTOMAFIGURE 2385 SECTION OF EMBRYONIC SHIELDFIGURES 2386 AND 2387 PRIMITIVE KIDNEYSFIGURE 2388 PIGEMBRYOFIGURE 2389 HUMAN EMBRYOFIGURES 2390 TO 2392 RUDIMENTARY KIDNEYS AND SEXUAL ORGANSFIGURES 2393 AND 2394 URINARY AND SEXUAL ORGANS OF SALAMANDERFIGURE 2395 PRIMITIVE KIDNEYS OF HUMAN EMBRYOFIGURES 2396 TO 2398 URINARY ORGANS OF OXEMBRYOSFIGURE 2399 SEXUAL ORGANS OF WATERMOLEFIGURES 2400 AND 2401 ORIGINAL POSITION OF SEXUAL GLANDSFIGURE 2402 UROGENITAL SYSTEM OF HUMAN EMBRYOFIGURE 2403 SECTION OF OVARYFIGURES 2404 TO 2406 GRAAFIAN FOLLICLESFIGURE 2407 A RIPE GRAAFIAN FOLLICLEFIGURE 2408 THE HUMAN OVUMCHAPTER 216 STRUCTURE OF THE LANCELET AND THE SEASQUIRTIn turning from the embryology to the phylogeny of manfrom thedevelopment of the individual to that of the specieswe must bear inmind the direct causal connection that exists between these two mainbranches of the science of human evolution This important causalnexus finds its simplest expression in the fundamental law of organicdevelopment the content and purport of which we have fullyconsidered in the first chapter According to this biogenetic lawontogeny is a brief and condensed recapitulation of phylogeny If thiscompendious reproduction were complete in all cases it would be veryeasy to construct the whole story of evolution on an embryonic basisWhen we