. The Batrachia of North America [microform]. Amphibians; Amphibiens. 14 BULLETIN Ml, UNITED STATES NATIONAL MUSEUM. Thii ('liariicters display-'d l).v tin? three divisions in question indicate their rehitionship to l)i'. iis Ibllows: The orders of JJivision I ])resent in their cranial structure a greater resembhiuce to the limblinned or cro8soi); siiHi iishes tlian do either of the others. The third division is the most divergent from tiie »y, and is in various respects tlie most speciaHzed. This si>ecialization consists not only in a departure from the i)rimitive Batrachia, but
. The Batrachia of North America [microform]. Amphibians; Amphibiens. 14 BULLETIN Ml, UNITED STATES NATIONAL MUSEUM. Thii ('liariicters display-'d l).v tin? three divisions in question indicate their rehitionship to l)i'. iis Ibllows: The orders of JJivision I ])resent in their cranial structure a greater resembhiuce to the limblinned or cro8soi); siiHi iishes tlian do either of the others. The third division is the most divergent from tiie »y, and is in various respects tlie most speciaHzed. This si>ecialization consists not only in a departure from the i)rimitive Batrachia, but also from all other forms of vertebrata. Its specialization is seen in the loss and cocissification of various parts of the skeleton. The ITnulehi display chara(;ters interme<liate between the extremes of the class. Near them the Trachystomata (SirenidaO are still more inferior by loss oi' parts of the skull ami of the pelvic arch. The Prnteida have lost the maxillary arch of the Stegocei)haIi, but re- tain their OS iiitercalare. IMIVLOGENV. The class IJatrachia holds an imi)()rtant position in the history of the vertebrata, as tlie first meudter of that kin;;dom which occupied the land on the advent of the conditions suitable for air-i)reatbiny types. It thus stands in relation to the lines of the Sauropsida and ^lammalia, and as the immediate descendants of the fishes. As rej^ards the extinct orders, the primitive type is evidently the (ranocephala. whose vertebral column displays an arrest of (diaracters which are transitional in the hij^aer vertebrata. From this group the orders ithachitomi, Fauboloi'ieri,and have been evidently derived. We may then present the followinj,' fjenealogical table of the class liatrachia: Salieutia. Tracbystoinata. Rhachitomi. Ganocephala. I I / N 1. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of
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Keywords: ., bookcentury1800, bookdecade1880, bookpubli, booksubjectamphibians
