. Text book of zoology. Zoology. rig. 326. Head, etc., of a, XJrodelan larva, diagrammatic (in the figure more of the thin plates is seen than in reality, etc.). h operculum, p thin plate on the first giU bar.—Orig. Urodeles; they are, however, soon covered by the operculum, which is well developed, and covers gills and gill-clefts, concrescing posteriorly with the surface of the body. A. large branchial cavityt results, communicating with the exterior by a single aperture,^ usually on the left side. The gills enclosed in this cavity atrophy, and in their place numerous branched "in- tern
. Text book of zoology. Zoology. rig. 326. Head, etc., of a, XJrodelan larva, diagrammatic (in the figure more of the thin plates is seen than in reality, etc.). h operculum, p thin plate on the first giU bar.—Orig. Urodeles; they are, however, soon covered by the operculum, which is well developed, and covers gills and gill-clefts, concrescing posteriorly with the surface of the body. A. large branchial cavityt results, communicating with the exterior by a single aperture,^ usually on the left side. The gills enclosed in this cavity atrophy, and in their place numerous branched "in- ternal gills," structures peculiar to the anuran larvae, arise on the outer edge of all the four bars. As in Selachians, etc., there is usually an imperfect straining apparatus at the inner edge of the gill-bar, in such forms as are provided with external gills. It is repre- sented on each arch by one or two (one on the lirst and fourth gill-bars, two on each of the others) rows of short processes. Fig. 327. A Young Tadpole of a frog (lateral view) ; B somewhat older from below; C stiU older larva with internal giUs. 1, 2, 3 the three external gills, u. anus, b hind limb, g branchial aperture, inu caudal muscles, n narea, o mouth, op operculum, s organ of adhesion.—C orig., A and B with the assistance of figures by Eeker. * In other embryos of this division there is, Instead of such gills, one very vascular lamina on each side. t The opercula of the two sides are continuous ventrally (Fig. 327 B), concrescing posteriorly to enclose a single cavity. J In Pipa, and an allied genus, there are two openings, one on either 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 Boas, J. E. V. (Johan Erik Vesti), 1855-1935; Boas, J. E. V. (Johan Erik Vesti), 1855-1935. Lehrbuch der Zoologie. London, Sampson Low
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
