3. Galaxias attenuatus inhabits Tasmania, New Zealand, the Falkland Islands, and the southernmost part of the South American continent.
4. Several Petromyzonts enter the fresh waters of Tasmania, South Australia, New Zealand, and Chili.
B. Genera identical in distant continents—
1. The genus Umbra, so peculiar a form as to be the type of a distinct family consisting of two most closely allied species only, one of which is found in the Atlantic States of North America, the other in the system of the Danube.
2. A very distinct genus of Sturgeons, Scaphirhynchus, consisting of two species only, one inhabiting fresh waters of Central Asia, the other the system of the Mississippi.
3. A second most peculiar genus of Sturgeons, Polyodon, consists likewise of two species only, one inhabiting the Mississippi, the other the Yang-tse-kiang.
4. Amiurus, a Siluroid, and Catostomus, a Cyprinoid genus, both well represented in North America, occur in a single species in temperate China.
5. Lepidosiren is represented by one species in tropical America, and by the second in tropical Africa (Protopterus).
6. Notopterus consists of three Indian and two West African species.
7. Mastacembelus and Ophiocephalus, genera characteristic of the Indian region, emerge severally by a single species in West and Central Africa.