418 REPORT—1905. 
Tun Cyprinibai.—These fishes, as mentioned above, ate very closely related 
to the preceding, and there is every reason to believe the former to be derived 
from the latter. Their least specialised genera (Catostomine) are now found in 
North and Central America (about sixty species), whilst three species, referable to 
the same genera, inhabit Hastern Siberiaand China. These Catestomine are known 
to have had representatives in the Hocene of North America, whilst the more 
specialised Cyprinine, which constitute the great bulk of the family both in the 
new world and in the old, have left remains in the Oligocene and later beds in 
North America and Europe. It is, therefore, highly probable that the Cyprinids 
originated as a northern offshoot of the South and Central American Characinids, 
and thence spread to Eastern Asia, at least as early as the Upper Eocene. By the 
time (Miocene) they had reached India, where they now form the great majority 
of the fresh-water fishes, Africa had been connected with it by a wide belt of land, 
and no obstacle prevented their western extension. This comparatively recent 
migration accounts for the practical identity of the genera and the often very 
close affinity of the species of the Cyprinids of India and Africa. At the same 
period the land-area connecting India and Africa with Madagascar had dis- 
appeared, and the Cyprinids never reached that great island, where no doubt they 
would have thriven, if we judge by the results of the introduction by man of the 
gold fish, said to be in process of strongly reducing the numbers of the native 
Malagassy fresh-water fishes with which it is in a position to compete. Com- 
petition is always an important factor in the distribution of a group of animals, 
and the confinement of the Characinids to the waters of the western and central 
parts of Africa at the time of the immigration of the Cyprinids from the east 
must be the explanation of the comparative abundance of the latter and the scarcity 
of the former in those parts of the continent east of the Rift Valley which are 
not drained by rivers flowing from the central parts. The Cyprinids must have 
spread more rapidly than the Characinids, and being also less partial to heat they 
have thriven in the waters of South Africa, where at present only two species of 
Characinids—both carnivorous forms—are known to extend south of the Zambesi 
system. Of the 202 species reeorded from Africa thirteen are found in North- 
West Africa, sixty-three in Hast Africa (exclusive of the Zambesi), and twenty- 
one in South Africa, 
Tre Srrurip#.—This large family is almost cosmopolitan in tropical and 
warm regions; and although the great bulk of the species are restricted to fresh 
waters, a certain number (chiefly of the sub-family Arie) occur on the coasts 
and in the estuaries. Morphologically these fishes are so closely allied to the 
Characinidze and Cyprinide that we must assume them to have been evolved from 
a common ancestral stock, probably in Cretaceous times; but connecting forms 
such as we should expect to find in deposits of that age are still unknown. The 
Silurids appear in the Lower Hocene estuarine beds of England and France, as forms 
closely related to the living Ariine and Bagrine, and further allied forms follow 
in the Middle Eocene of various parts of Europe and North America, In the 
Upper Eocene of Lower Egypt estuarine deposits contain well-preserved remains 
of forms which appear to be only specifically separable from the Bagrus still living 
in the Nile. 
The general distribution of these fishes was, therefore, in early Tertiary times 
very much the same as it is at present, and paleontology offers us no clue as to 
where they originated. The most generalised Silurid known at present { Diplomys- 
tus) is now living in South America. The resemblance between certain African 
and South American genera placed together under the sub-family Doradine might 
suggest a former communication between these parts of the world; but we 
must bear in mind that the same sub-family is also represented in South-Eastern 
Asia, and as far back in time as the Miocene (Bagartus gigas). Leriche, who 
has recently reviewed our knowledge of the fossil Silurids, follows Verbeck in 
regarding the Padang lignites whence Giinther described this Bagarius and other 
fresh-water fishes as Middle Eocene; but at that time, according to de Lapparent, 
Sumatra was entirely under the sea; and Dr. Smith Woodward agrees with me 
in thinking thet the beds in question must be more recent than Eocene, 
