. Zoology : for students and general readers . Zoology. 4U8 ZOOLOGY. phibians having a middle ear in addition to the internal ear of fishes. In toads and frogs the tongue is quite free and capable of being protruded, except in Pijxi, and Dactyle- tlira, where it is entirely wanting. In other forms the tongue is much as in fishes, not being capable of extension from the mouth. As in fishes, there are no salivary glands. The gills of Am- phibians consist of two or three pairs of branched, fleshy appendages, which gro-ff out from as many arches. "While in the toad and frog the gills are smal
. Zoology : for students and general readers . Zoology. 4U8 ZOOLOGY. phibians having a middle ear in addition to the internal ear of fishes. In toads and frogs the tongue is quite free and capable of being protruded, except in Pijxi, and Dactyle- tlira, where it is entirely wanting. In other forms the tongue is much as in fishes, not being capable of extension from the mouth. As in fishes, there are no salivary glands. The gills of Am- phibians consist of two or three pairs of branched, fleshy appendages, which gro-ff out from as many arches. "While in the toad and frog the gills are small and remain but for a short time, in the larval salaman- ders, especially the axolotl (Fig. 430), the gills are still longer retained, while in the mud-puppy [Necturus) they 2)ersist throughout life. The digestive canal is us- irally simple, straight, there being no enlargement form- ing a stomach; in other species, both tailless and tailed, the canal dilates into a stomach, which in the toad lies across the body- cavity. In tadpoles, which live on decaying vegeta])le matter, the digestive tract is very long and closely coil- ed (Fig. 431). sacs, much like those of the. Fig. 430.—,4a'ofo^?, or larval Salamander, ehovviiigthe gilln, heart iH), aortic branches and lungs (PA). P, pulmonary arleries ; pp, pidmonary veins ; A, bnlbus arteriot^us from which the vas^cular arches (5) origi- nate ; bb, branchial vein ; the , Acna cava ; V, descending aorta.—From Gervais et Van Beneden. The lungs are long, slender ab- Dipnoan Lejndosiren, which extend backwards into the domen, as in the lizards and snakes, no diaphi-agm existing to confine them in a thoracic cavity. The larynx exists in it \ery rudimentary sttite, though the vocal powers of the. 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
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1879
