. Evolution and animal life; an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animals . FIG. 107.—Head of a five-months human embryoshowing embryonic hair-covering. (After Ecker.) HEREDITY 175. FIG. 108. — Andrian Jeftichjew, theRussian dog man, showing extraor-dinary covering of hair on the face.(After Wiedersheim.) developed in the embryo than inthe adult, becoming atrophiedwith age. Familiar examplesare the appendix vermiformisand the unused muscles of theears in man, the atrophied lung,pelvis, and limbs of the snake,the air bladder of th
. Evolution and animal life; an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animals . FIG. 107.—Head of a five-months human embryoshowing embryonic hair-covering. (After Ecker.) HEREDITY 175. FIG. 108. — Andrian Jeftichjew, theRussian dog man, showing extraor-dinary covering of hair on the face.(After Wiedersheim.) developed in the embryo than inthe adult, becoming atrophiedwith age. Familiar examplesare the appendix vermiformisand the unused muscles of theears in man, the atrophied lung,pelvis, and limbs of the snake,the air bladder of the fish, thethumb (or rather index fin-ger), of the bird, the splint boneof the horse, and the like. The anatomist Wiedersheimhas recorded 180 vestigial or-gans in man. These structuresoccur in all the systems oforgans, integument, skeleton,muscles, nervous system, senseorgans, digestive, respiratory, circulatory, and urino-genital systems. Most of these rem-nants of structures are to be found completely developed inother vertebrate groups. Eleven of them are characteristicas functional organs of fishes only, four of amphibians andreptiles. The fact that structures are vestigial is shown often by cases of atavistic de-velopment. Within t
Size: 1437px × 1740px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorkelloggvernonlvernonl, bookcentury1900, bookdecade1900
