. The biology of the amphibia. Amphibians. RELATIONSHIPS AND CLASSIFICATION 513 the most distinctive is the small Triprion petasatus of Yucatan. The casque formation in this species has led to a widening of the ethmoid, a reduction in length of the palatines, and a broadening of the parasphenoid. The last group of Hylinae is characterized by a vertical pupil. This is not a good character, for it has arisen independently in H. vasta and in H. lichenata of the West Indies (see page 89), also independently—to judge from the numerous differences which distinguish grand from papua—in the two Papuan
. The biology of the amphibia. Amphibians. RELATIONSHIPS AND CLASSIFICATION 513 the most distinctive is the small Triprion petasatus of Yucatan. The casque formation in this species has led to a widening of the ethmoid, a reduction in length of the palatines, and a broadening of the parasphenoid. The last group of Hylinae is characterized by a vertical pupil. This is not a good character, for it has arisen independently in H. vasta and in H. lichenata of the West Indies (see page 89), also independently—to judge from the numerous differences which distinguish grand from papua—in the two Papuan species which have been linked together under the name of "Nyctimy- ; In general, pupil form does not seem a reliable character in the Hylidae to distinguish related groups of species, for in this. Fig. 169.—Phyllomedusa bicolor, a South American tree frog possessing both opposable thumbs and inner toes. family the pupil has changed its form too frequently. There is, however, one group of neotropical Hylinae which has added to the pupil character certain other features which seem to distin- guish them as a natural group of species. These species are referred to Phyllomedusa (including Agalychnis). They are hylas which have developed a bright green color (sometimes brown in young), usually a red iris, a vertical pupil, and, most important of all, a disproportionate growth of the toes. The more primitive species, moreleti, calcarifer, and spurrelli, differ from Hyla in toe proportions, the disc of the first reaching the base of the disc of the second and not falling much short of this point, as in Hyla. They have broadly webbed toes and look like large specimens of Hyla uranochroa or H. pulchella except for their pupil form and toe proportions. The other species of Phyllome- dusa show more or less reduction of the webs, an elongation of the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabi
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Keywords: ., bookcentury1900, bookpublishernewyorkmcgr, booksubjectamphibians
