General principles of zoology . FIG. 4.—Tadpoles of Jfana teniporaria. »i, mouth; g, upper jaw ; z, lower jaw ; s, suckingdisk ; kb, external gills ; ik, region of the internal gills ; «, nose ; a, eye ; 0, auditoryvesicle ; A, cardiac region ; </, operculum. amples will show: (i) In the early stages of developmentthe human embryo (Fig. 3) possesses remaikable resem- HISTORY OF ZOOLOGY. 4J. blances to the lowest vertebrates, the fishes. Like theseit has gill-slits, the same arrangement of the heart and ofthe arterial vessels, certain fundamental features in thedevelopment of the skeleton, e
General principles of zoology . FIG. 4.—Tadpoles of Jfana teniporaria. »i, mouth; g, upper jaw ; z, lower jaw ; s, suckingdisk ; kb, external gills ; ik, region of the internal gills ; «, nose ; a, eye ; 0, auditoryvesicle ; A, cardiac region ; </, operculum. amples will show: (i) In the early stages of developmentthe human embryo (Fig. 3) possesses remaikable resem- HISTORY OF ZOOLOGY. 4J. blances to the lowest vertebrates, the fishes. Like theseit has gill-slits, the same arrangement of the heart and ofthe arterial vessels, certain fundamental features in thedevelopment of the skeleton, etc. (2) Frogs in theirtadpole stage have an organization similar to that, whichremains permanent in the case of certain amphibia, thePerennibranchiata (Fig. 5), which stand lower in the sys-. FIG. 5.—Siredonpisciformis (Axolotl). (After Dumeril and liibron.) tern; they have a rudimentary tail and tuft-like gillsrwhich are lacking in the adult frog. (3) There are cer-tain parasitic crabs, which live upon the gills of fishes, and
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
