. The biology of the frog . FIG. 24. — Embryos. Gp, gill plate; Gs, Gs, two gill slits ; S, suckers ; Sp,sense plate ; An, anus. (From Morgan, after Schultze.) the tadpole leaves the jelly. In the middle line, justabove the ventral sucker, the beginning of the mouthappears as a hollow depression of the ectoderm, but itdoes not communicate with the archenteron until a muchlater period. The anus begins as an invagination of theectoderm a short distance behind the point where the 102 THE BIOLOGY OF THE FROG chap. blastopore was closed over. Later this invagination meetsand fuses with a diverticul
. The biology of the frog . FIG. 24. — Embryos. Gp, gill plate; Gs, Gs, two gill slits ; S, suckers ; Sp,sense plate ; An, anus. (From Morgan, after Schultze.) the tadpole leaves the jelly. In the middle line, justabove the ventral sucker, the beginning of the mouthappears as a hollow depression of the ectoderm, but itdoes not communicate with the archenteron until a muchlater period. The anus begins as an invagination of theectoderm a short distance behind the point where the 102 THE BIOLOGY OF THE FROG chap. blastopore was closed over. Later this invagination meetsand fuses with a diverticulum from the posterior part of thearchenteron, thus establishing an opening between the latterand the exterior. The tail arises as an elevation of theregion in front of the blastopore, which grows backward andpushes the anus to a more ventral position. Later it be-comes flattened from side to side, and its upper and loweredges become produced into a thin expansion, or tailfin. The nostrils appear as a pair of external depr
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Keywords: ., boo, bookcentury1900, bookdecade1900, bookidbiologyoffrog1907holm
