TELEOSTE, 578 
which they swallow whole. They are the largest fresh-water fishes, 
for A. sturdo may attain a length of 18 ft. and a weight of 600 lb., 
while the 4. uso of Southern Russia may measure 25 {t. and weigh 
nearly 3000 lb, !' Most of the species are found both in the sea and in 
rivers or lakes. The roes or ovaries form caviare; the gelatinous 
internal layer of the swim-bladder is used as isinglass. 
The genus Scaphirhynchus is represented in Asia and the United 
States ; Polyodon or Spatularia spatula is the paddle-fish or spoon-bill 
of the Mississippi. 
Order 3. Ho.ostE1 !—with bony skeleton 
Living examples :—Lepidosteus and Amia. 
Extinct examples :—Lepidotus, Pycnodus, Aspidorhynchus. 
The N. American bony pike—Zefidosteus—is covered 
with rows of “ganoid” scales; the whole skeleton is well 
ossified, and the vertebral bodies are opisthoccelous; the 
swim-bladder is like a lung in structure, and to some 
degree in function. The bow-fin, Ama calva, frequenting 
still waters in the United States, has a similar lung-like 
swim-bladder. Its scales are similar to those of a Teleost. 
Order 4. TELEostTe1. The “ Bony Fishes” 
This order includes most of the fishes now alive. 
Though comparatively modern fishes, they are older than 
was formerly supposed, as several Jurassic genera (Zhrissops, 
Leptolepis, etc.), which used to be classed as “ Ganoids,” 4 
must be considered as actual Clupeoids, or herring-like 
Teleostei. It is, however, not until the Upper Cretaceous 
and Tertiary epochs that they assume among fishes that 
overwhelming preponderance in numbers which they possess 
at the present day. The physostomous type of Teleostean 
is the most ancient, and probably stands in a continuous 
genetic line with the Holostei. 
The skeleton is well ossified, with numerous investing 
bones on the skull, others in the operculum, and on the 
shoulder-girdle. There is always a supra-occipital in the 
1 The term ‘ Ganoids,” which we abandon, is often used to include 
Crossopterygii, Chondrostei, and Holostei. Though they agree in 
having « conus arteriosus with many valves, as opposed to the 
Teleostean bulbus, an optic chiasma, as opposed to the decussate 
condition in Teleosts, and an intestinal spiral valve which is absent in 
Teleosts, they do not seem to form a natural division. 
