. The biology of the amphibia. Amphibians. RELATIONSHIPS AND CLASSIFICATION 505 linae are merely slightly modified members of the Physalaemus stock. Paludicola, in the broad sense, is such a widespread stock, of such varied body form and color, that it affords a possible ancestor for the other groups. Leptodactylus is the most dominant group of Leptodactylinae. It includes the so-called " South American Bull ; Most of the species are Rana- like in appearance except for their prac- tically webless toes. Some species of Physalaemus resemble some forms of Leptodactylus closely. Fa
. The biology of the amphibia. Amphibians. RELATIONSHIPS AND CLASSIFICATION 505 linae are merely slightly modified members of the Physalaemus stock. Paludicola, in the broad sense, is such a widespread stock, of such varied body form and color, that it affords a possible ancestor for the other groups. Leptodactylus is the most dominant group of Leptodactylinae. It includes the so-called " South American Bull ; Most of the species are Rana- like in appearance except for their prac- tically webless toes. Some species of Physalaemus resemble some forms of Leptodactylus closely. Family 3. Brachycephalidae.—A large group of small neotropical toads has recently been shown to be closely allied to the Bufonidae and to have no relation- ship to the Ranidae or Brevicipitidae with which they were formerly confused. They may be described as Procoela with the two halves of the pectoral girdle partly or wholly fused in the midline. They differ from the Diplasiocoela not only in their uniformly procoelous vertebral column but also in their bufonid-like thigh muscles (the tendon of the semitendinosus passes ventral to that of the gracilis major and minor, not dorsal to it, as in the Diplasio- coela) . The family is primarily terrestrial, and intercalary cartilages are lacking. The various genera frequently exhibit fusions in the vertebrae. In one genus from Mount Roraima (Oreophrynella), there are only five presacral segments seventh, eighth, and ninth, (Fig. 164). The firmisternous condition are fused- of the pectoral girdle has been assumed at least three times within the family, once in each of the three subfamilies. The Brachycephalidae show more clearly than any other family of Salientia the details of their origin. Each subfamily has arisen from a different stock of bufonids, but as all the ancestral stocks were bufonids residing in the same general region, the Brachy- cephalidae may be considered a natural, even though a com- posite, family. It is interesti
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Keywords: ., bookcentury1900, bookpublishernewyorkmcgr, booksubjectamphibians
