According to the views generally adopted at present, all those Vertebrate animals are referred to the Class of Fishes, which living in water, breathe air dissolved in water by means of gills or branchiae, whose heart consists of a single ventricle and single atrium, whose limbs, if present are modified into fins, supplemented by unpaired, median fins, and whose skin is either naked or covered with scales of osseous plates or bucklers. With few exceptions fishes ...
The Outline of Science: A Plain Story Simply Told (In 2 Volumes)
