The evolution of man: a popular exposition of the principal points of human ontogeny and phylogene . s-sively in the different periods of its tribal history. Thefirst rudiment of the organ of smell in the embryo of Manand in that of all the higher Mammals, makes its appearancein the same entirely simple form which is retained throughoutlife by the nose of Fishes. At a very early stage, andwhile no trace of the characteristic facial structure of Manis yet visible, a pair of small grooves appear on the frontof the head, and before the primitive mouth-cavity; thesewere first discovered by Baer, a
The evolution of man: a popular exposition of the principal points of human ontogeny and phylogene . s-sively in the different periods of its tribal history. Thefirst rudiment of the organ of smell in the embryo of Manand in that of all the higher Mammals, makes its appearancein the same entirely simple form which is retained throughoutlife by the nose of Fishes. At a very early stage, andwhile no trace of the characteristic facial structure of Manis yet visible, a pair of small grooves appear on the frontof the head, and before the primitive mouth-cavity; thesewere first discovered by Baer, and by him properly enoughnamed * olfactory grooves ( Kiechgruben, Figs. 232, n,233, n). These primitive nasal grooves are quite separatefrom the primitive mouth-cavity, or mouth indentation,which, as we found, likewise makes its appearance as agroove-like indentation of the external skin-covering, infront of the blind anterior extremity of the intestinal canal DEVELOPMENT OF THE NOSE. 243 This pair of nasal grooves, as well as the single mouthgroove (Fig. 235, m), is lined by the horn-plate. The. Fig. 232. Fig. 233.
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Keywords: ., bookcentury1800, booksubjectembryologyhu, booksubjecthumanbeings
