. The biology of the amphibia. Amphibians. 528 THE BIOLOGY OF THE AMPHIBIA. evolution and groups which have descended from a common ancestor. The present arrange- ment, although not entirely satisfactory, will serve to iden- tify the more conspicuous groups of genera. Three genera have been placed in separate monotypic subfamilies. When the anatomy of other Brevici- pitidae becomes better known, they will probably be grouped with other genera, but at the present moment their immedi- ate relationships are unknown. Subfamily 1. Dyscophinae. —Brevicipitids with large, en- tire prevomers, surround
. The biology of the amphibia. Amphibians. 528 THE BIOLOGY OF THE AMPHIBIA. evolution and groups which have descended from a common ancestor. The present arrange- ment, although not entirely satisfactory, will serve to iden- tify the more conspicuous groups of genera. Three genera have been placed in separate monotypic subfamilies. When the anatomy of other Brevici- pitidae becomes better known, they will probably be grouped with other genera, but at the present moment their immedi- ate relationships are unknown. Subfamily 1. Dyscophinae. —Brevicipitids with large, en- tire prevomers, surrounding the internal nares except on the outer side; omosternum, clavi- cles, procoracoids, and sternum present. Dyscophus of Mada- gascar and Calluella of Suma- tra, India, and southern China are the most primitive genera. They agree in having large pre- vomers with the teeth arranged in a transverse row behind the internal nares. The sacrum in these genera is only slightly dilated, the omosternum is small. They possess maxillary teeth and resemble sorial species of Rana in general appearance. From these two stocks there has arisen in differ- ent regions a host of genera. Only three of these derived genera have diverged so slightly from the ancestral stocks that they are grouped in the same subfamily with 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 Noble, Gladwyn Kingsley, 1894-1940. New York : McGraw-Hill
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