[23] One species (Arius thalassinus) found in Indian and African rivers.
[24] This species extends from India into East Africa.
[25] We have left out from these considerations the Ariina and Cyprinodonts, which can pass with impunity through salt water, and are spread over much larger areas.
[26] Cope has discovered in a tertiary freshwater-deposit at Idaho an extinct genus of this group, Diastichus. He considers this interesting fact to be strongly suggestive of continuity of territory of Asia and North America.—“Proc. Am. Phil. Soc. 1873,” p. 55.
[27] Leidy describes a Siluroid (Pimelodus) from tertiary deposits of Wyoming Territory. “Contrib. to the Extinct Vert. Fauna of the Western Territ. 1873,” p. 193.
[28] The genera peculiar to the Equatorial zone are printed in italics.
[29] Number of species uncertain.
[30] See p. 151, Fig. 67.
[31] See p. 128, Fig. 55.
[32] See p. 104.