. Biologia centrali-americana. Pisces. Zoology; Fishes; Zoology. XX INTRODUCTION. pterygii, ^Yhich were abundant in Cretaceous seas ; no prae-tertiary Ostariophysi have been found, but Siluridse occur in the eailiest Eocene deposits. A¥ith the exception of the Silurid genera Arius, Plotosus, and a few allied to them, which have become estuarine or marine, all the members of the group are fresh-water fishes. The Gymnotidse and Cyprinida^ are evidently modified Characiuid;^, whilst the LoricariidiB and Aspredinidae have been derived from the Silurid;^. The Characinidte and Siluridae, however, ar
. Biologia centrali-americana. Pisces. Zoology; Fishes; Zoology. XX INTRODUCTION. pterygii, ^Yhich were abundant in Cretaceous seas ; no prae-tertiary Ostariophysi have been found, but Siluridse occur in the eailiest Eocene deposits. A¥ith the exception of the Silurid genera Arius, Plotosus, and a few allied to them, which have become estuarine or marine, all the members of the group are fresh-water fishes. The Gymnotidse and Cyprinida^ are evidently modified Characiuid;^, whilst the LoricariidiB and Aspredinidae have been derived from the Silurid;^. The Characinidte and Siluridae, however, are by no means closely related, although evidently derived from the same stock, as is shown by the presence in both of the remarkable chain of " Weberian ossicles" connecting the air-bladder with the auditory organ. The origin and distribution of the Mexican and Central-American families of this group may now be discussed. The family Characinid^ is very abundant in the fresh waters of South America, where more than 500 species are known to occur and where the genera are numerous and. DrsimmjTioN or CnAKAcjNiri^'E. very diversified. The most generalized types also occur in this continent, which must be regarded as the original home of the group. In Africa there are about 100 species but the family is not represented in Madagascar. None of the genera are common to. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Godman, Frederick Du Cane, 1834-1919. ed; Regan, Charles Tate, 1878-. [London, Pub. for the editor by R. H. Porter]
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