The evolution of man: a popular exposition of the principal points of human ontogeny and phylogenyFrom the German of Ernst Haeckel . all specific points the human noseexactly resembles that of the Catarhine Apes, some of whichindeed possess an entirely human external nose (see faceof the Nose-ape, Fig. 202, p. 175). The first rudiment of theolfactory organ in the human embryo does not, however,show any signs of the fine form of the future catarhinenose. Indeed, it first appears in the same form whichpersists for life in Fishes; in the form of two simple pits, THE NOSE. 241 or grooves in the sk
The evolution of man: a popular exposition of the principal points of human ontogeny and phylogenyFrom the German of Ernst Haeckel . all specific points the human noseexactly resembles that of the Catarhine Apes, some of whichindeed possess an entirely human external nose (see faceof the Nose-ape, Fig. 202, p. 175). The first rudiment of theolfactory organ in the human embryo does not, however,show any signs of the fine form of the future catarhinenose. Indeed, it first appears in the same form whichpersists for life in Fishes; in the form of two simple pits, THE NOSE. 241 or grooves in the skin of the upper surface of the head. Inall Fishes two of these mere blind nose-pits are found intho upper surface of the head ; sometimes they are situatedat the back, near the eyes, sometimes near the snout, or,again, near the mouth-opening (Fig. 191, n, p. 113). They arelined by mucous membrane in folds, over which the endbranches of the olfactory nerves spread. In this its original condition the double nose of allAmphirhina (p. 101) is entirely unconnected with the pri-mitive mouth-cavity. The connection, however, begins to. m Fig. 231.—Head of a Shark [Scyl-lium), from the ventral side : m, mouthopening; o, nose grooves, or pits; r,nasal furrow; n, nose-flap in itsnatural position; n, nose-flap turnedup. (The dots are openings of mucousducts.) (After Gegenbaur.) appear even in some Primitive Fishes {Selachii); a super-ficial skin-furrow extends on each side from the nose-groovedown to the adjacent corner of the mouth. This furrow,the nasal channel, or furrow (Fig. 231, r), is of great sig-nificance. In many Sharks (, Scyllium) a special processof the frontal skin, the nasal flap, or inner nasal process,overlaps the nasal furrow (n, n). Opposite to this the outeredge of the furrow rises and forms the outer nasal Dipneusta and Amphibia these two nasal processes meetover the furrow and coalesce, thus forming a canal, the nasal canal. There is now a passage fro
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Keywords: ., bookcentury1800, booksubjectembryology, booksubjectembryologyhum
