. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. GILLS OF BATRACIIIA. 313 341. artery to its ventricular origin is not effected until the batracliian type is passed. In the lower or percnnibranchiate members of the order, the single artery from the ventricle sends, as in Fishes, the whole of the Ijlood jn-imarily to branchial organs, throughout life, and, in all Batradiia, at the eaidier aquatic period of existence ; a description of the gills, permanent or deciduous, will, therefore, be premised. At page 87 are described and figured, fig. 69, the hyo-branchial arch an
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. GILLS OF BATRACIIIA. 313 341. artery to its ventricular origin is not effected until the batracliian type is passed. In the lower or percnnibranchiate members of the order, the single artery from the ventricle sends, as in Fishes, the whole of the Ijlood jn-imarily to branchial organs, throughout life, and, in all Batradiia, at the eaidier aquatic period of existence ; a description of the gills, permanent or deciduous, will, therefore, be premised. At page 87 are described and figured, fig. 69, the hyo-branchial arch and appendages of the larva of the Fmg. The basihyal, h, suspended l)y cera- tohj'als, a, to the tympanic pedicle, e, supports a pair of cerato-branohials, c, which each send off four branchial arches. All these parts are cartilao-e. The heart distributes the blood by a short trunk througli four pairs of vas- cular arches, wliich, bending round the gullet, reunite behind to form the aorta. Before the larva quits the egg, a tegumentary tubercle buds OTit in front of the branchial cleft, and soon shoots into a trifid appendage, fig. 341, A and B, each process lengthening and is extricated. These filaments, of cylindrical shape, ib. C, each suj^port a single cajiillary loop, pushed out from the S'i2 primitive vascular arch, and are covered by ciliated epi- thelium, producing the cur- rents indicated by the arrows in c. The branchial cavity communicates at first, as in Br and do stoma, with the abdominal one, as well as with the outer surface by the branchial clefts. About the fourth day these simple outer gills begin to shrink ; they are absorbed by the seventh day. The cartilaginous arches, also beginning to shrink, become more internal by the progressive growth of the head. In the Newt ( Triton, fig. 342), three pairs of external gills are developed, at first as simple filaments, each with its capillary VOL. I. L L Ifurcating after the lar •va. Please note that these images are
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
