Alfred Russel Wallace

“ Fresh-water Fish.—There are 36 families of fishes which inhabit fresh water exclusively, and 5 others, which are both marine and fresh-water. These present many interesting peculiarities of distribution. The Neotropical region is the richest in families, and probably also in genera and species. No less than 22 families inhabit it, and of these 6 are altogether peculiar. The Ethiopian and Nearctic regions each have 18 families, the former with 3, and the latter with 5 peculiar. Several isolated forms, requiring to be placed in distinct families, inhabit the great American lakes ”

“ Most of these fossils represent marine fishes, those of fresh-water origin being rare, and of little importance as an aid in determining the causes of the distribution of living forms. To understand this we must look to the various changes of the land surface which have led to the existing distribution of all the higher vertebrates, and to those special means of dispersal which Mr. Darwin has shown to be possessed by all fresh-water productions. ”

“ Sub-family 4 (Siluridæ Proteropteræ) ranges over all the tropical and most of the temperate parts of the globe, except Europe and Australia. It consists of four groups: Bagrina (16 genera) , ranging over most of the Old World and North America; Pimelodina (15 genera) , confined to Tropical America, except one genus which is African; Ariina (10 genera) , all Tropical regions; and Bagarina (3 genera) , Oriental region. The distribution of the genera is as follows:—
Bagrus (2 sp.) , Nile; Chrysichthys (5 sp.) , Tropical Africa ”

“ We may therefore be sure that the Upper Silurian rocks in which these are found, although so very far back in geological history, do not by any means lead us to the time when the primitive fish-type appeared upon the earth. ”

“ All the ancient fossil fishes belong to the above-mentioned groups, and many of them have little resemblance to existing forms. The Teleostean fishes, which form the great bulk of those now living, cannot be traced back further than the Cretaceous period, while by far the larger number first appear in the Tertiary beds. ”

“ A species of Dentex has occurred on the English coast, and this seems to be the extreme northern range of the family, which does not regularly extend beyond the coast of Portugal, and in the East to Japan. ”

“ Carnivorous fishes, with elongate low, naked, or scaly bodies, living at the bottom of the shallow seas or fresh waters of temperate or tropical regions. Individuals of the same species often differ in inhabiting exclusively fresh or salt water. ”

“ Family 54.—GADIDÆ. (21 Genera, 58 Species.)
"Marine fishes, with more or less elongate bodies covered with small smooth scales."
Distribution.—Cold and temperate regions of both hemispheres; in the North extending as far south as the Mediterranean, Canary Islands, New York and Japan (and one species to the Philippines and Bay of Bengal) , and in the South to Chili and New Zealand.
Gadus (Cod) , Merluccius (Hake) , Phycis, Lota, Molva, Couchia, Motella, and Raniceps, are British. Lota inhabits fresh waters. ”

“ Ptyonotus (1 sp.) is confined to Lake Ontario. The Cataphracti (5 genera, 23 species) have also a wide range; one genus, Agonus, is found in the British seas, and also in Kamschatka and on the coast of Chili. Peristethus is also British.
Family 11.—TRACHINIDÆ (24 Genera, 90 Species.)
"Carnivorous marine fishes, with elongate bodies, living at the bottom, near the shore." ”