. Zoology. Zoology. 178 ZOOLOGY. coiled in a close spiral. Tlie mouth is small (Fig. 225, J), ^ with no tongue and only horny toothless jaws. The vertebrae of the tadpole are biconcave as in fishes, afterwards becoming con- verted into cup-and-ball joints. The accompanying figures rep- resent the external changes of tlie toad from the time it is hatched until the form of the adult is at- tained. The tadpoles of our Amer- ican toad are smaller and blacker in all stages of growth than those of the frog. The tadpole is at first without any limbs (Fig. 226, Mouth and digestive A), and with two pai
. Zoology. Zoology. 178 ZOOLOGY. coiled in a close spiral. Tlie mouth is small (Fig. 225, J), ^ with no tongue and only horny toothless jaws. The vertebrae of the tadpole are biconcave as in fishes, afterwards becoming con- verted into cup-and-ball joints. The accompanying figures rep- resent the external changes of tlie toad from the time it is hatched until the form of the adult is at- tained. The tadpoles of our Amer- ican toad are smaller and blacker in all stages of growth than those of the frog. The tadpole is at first without any limbs (Fig. 226, Mouth and digestive A), and with two pairs of gills; soon the hinder pair bud out. After this stage {E) is reached, the body begins to diminish in size. Then the fore-legs grow out (C); and finally, as at D, the tail is mostly absorbed, and at E we see the little toad which hops about on the Fio. 22.').- eanal of a Tadpole. A. mouth; b, intestine coileil on itself; c, liver; d. hepatic duct; e, pan- creas; y, rudimentary hind legs; <7, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Packard, A. S. (Alpheus Spring), 1839-1905. N. Y. , Holt
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1897
