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By Karl Patterson Schmidt It was not until after the publication of "The Frog Book," by Miss Mary C. Dickerson (1907), that the distribution of the two common toads of eastern North America was at all understood. Even the constant differences between the two species, Bufo americanus and Bufo fowleri, were overlooked until the herpetologists of the country became familiar with the voices of both species. Attention once drawn to the very great difference in their voices, it was found that they are really very distinct species with different, though overlapping, distribution, and even with entirely different breeding seasons. Bufo fowleri was, at first, thought to be a local variety in Massachusetts, but in a few years, after Miss Dickerson's recognition of its true characters, it was found to be the common toad of the Atlantic and Gulf Coastal Plains, ranging west to Texas and Missouri.
In collecting at Shanghai for the U.S. National Museum, Mr. Sowerby secured a large series of Bufo bufo asiaticus, indistinguishable from the common toad of the more northern provinces, Shantung, Chihli, and Shansi. Dr. Stejneger records, with some surprise, three specimens of Bufo bankorensis Barbour. from Suifu and Shen-kai-si, Szechwan, which he is unable to distinguish from the Formosan types of the species.
It is very evident that the relations of these two species in the Yangtze Valley, offer an interesting problem in field zoology to students who may be able to examine living material, listen to voices, study breeding habits and breeding seasons, and thus define the two forms more accurately than is at present possible. The two species are readily distinguishable in the adults by the smooth top of the head in bankorefl8is, the head of asiaticus being set with round warts; baakorensis, in addition, has shorter limbs and a shorter, wider head.
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From the collections of Chinese toads, studied by Dr. Stejneger and myself, it appears that a similar problem exists concerning the relations of the two common species of toads in Central China. In Stejneger's nomenclature, these are at present known as Bufo bufo asiaticus and Bufo bankorensis.
To my even greater surprise, the large series of toads collected at Ningkwo and Wuhu, Anhwei Province, by Mr. Clifford H. Pope for the Third Asiatic Expedition of the American Museum of Natural History, prove to belong to Bufo bankorensis instead of to the species common at Shanghai and Peking. A few specimens of baflkoren8is were collected from the Tei Pei Shan, Tsing Ling Mountains, Shensi, by the same expedition. Finally, specimens received by the National Museum and by the Field Museum of Natural History from my sometime associate at Cornell University, Dr. C. Ping, of the National Southeastern University, indicate that both species may occur near Nanking.
This pair of Chinese toad-species presents an interesting parallel to the pair of allied forms in the United States. Bufo bufo asiaticus is a northern species like Bufo americanus, extending far to the south in Eastern China, as americanus does in the eastern United States. Like Bufo fowleri, Bufo bankorensis was described from specimens at the limit of its range, and it was at first supposed to be confined to Formosa. The range of both species has subsequently proved to be enormously greater than was at first supposed.
The names applied to these two species are by no means well established. Bufo gargarizans, described from Chusan Island by Cantor in 1842, long antedates asiaticus and should probably replace this name. Specimens of the common toad of Chusan Island are required to settle this question is just possible that it may prove to be bankorensis . It is also possible that the comparison of large series of true Bufo bankorensis from Formosa with the supposed bankorensis from the mainland of China may prove them to be distinguishable. Finally, the types of Bufo gargarizans and of Bufo asiaticus should be re-examined in the light of the present data.