. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. DEVELOPEMENT OE BATEACHIA. G23 fovining the intestinal canal, h., excludes a portion of the yolk, v: the tegumcntary or 'serous' lay- ^3^^ er, a, accompanies the ' mucous ' layer, i, in the process of severing the vitelline from the intestinal cavities, and an outer yolk, or ' vi- tcllicle,' results. The embryo of the Frog is ex- tricated at a less advanced stage of developement than that of any other vertebrate animal: the neu- ral laminoj have united along the i-»"eitnJ""iscctiu„,EmiHToorFi8h. tru
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. DEVELOPEMENT OE BATEACHIA. G23 fovining the intestinal canal, h., excludes a portion of the yolk, v: the tegumcntary or 'serous' lay- ^3^^ er, a, accompanies the ' mucous ' layer, i, in the process of severing the vitelline from the intestinal cavities, and an outer yolk, or ' vi- tcllicle,' results. The embryo of the Frog is ex- tricated at a less advanced stage of developement than that of any other vertebrate animal: the neu- ral laminoj have united along the i-»"eitnJ""iscctiu„,EmiHToorFi8h. trunk, and two of the hromal arches have become complete below the head, but, in other parts, the neural and hremal canals are closed only by the corresponding laminaj in a state of mem- brane, the original investing membrane of the yolk lacing retained over all. After extrication, the tadpole rapidly grows, and the chief change of form is witnessed in the gills: each of the two lateral gills puts forth four plates, which have vascular and richly ciliated surfaces, fig. 430, c : a short additional leaflet is sometimes deve- loped from the base of the hinder gill. ' The current of the blood poured in regvdar pulsations at each contraction of the heart passes up each stem or main branch of the branchiffi, and a distinct stream is given off to each leaf; it is propelled to the extremity, and then returns down the opposite sides in the most regular manner, and the parts are so transparent that every globule of blood is distinctly and beautifully ; The first cutaneous mouth is defined by epidermal jaws, in the form of a very short transversely extended beak, fig. 433, 22, sur- rounded by a lip armed with minute rasp-like denticles, and aided by the pair of cephalic suckers projecting behind the mouth. Tlie wide pharynx, communicating also with the outer world by the lateral branchial slits, is extended posteriorly by a short ccsopliagns to a simple gastric enlargement,
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
