CHAPTER XXI 
TELEOSTEI: GENERAL CHARACTERS—-MALACOPTERYGII— 
OSTARIOPHYSI 
Order IV. Teleostei.' 
AS stated above (p. 495), the Holostean Ganoids pass very 
gradually into the Teleosteans, the lower groups of which appear 
to have been directly derived from them. The precise defini- 
tion of the Order Teleostei, as compared with the Ganoid Order 
Holostei, is a matter of some difficulty. The most important 
character appears to be the presence of an ossified supraoccipital 
bone.” Remnants of primitive characters, such as ganoid scales, 
fulera, rudiments of a splenial bone, spiral valve to the intes- 
tine, multivalvular conus arteriosus, are still found in some 
lower Teleosteans, but no longer in that combination which 
serves to define the preceding order. Although A/bula is excep- 
tional among all Teleosteans in having two transverse series of 
valves to the bulbus arteriosus instead of one, no Ganoid has 
fewer than three. 
The first remains of Teleosteans appear scantily in the Upper 
Trias, and it is not before we reach the Upper Cretaceous that 
they assume preponderance over other Teleostomes; whilst in 
the Upper Eocene they have already attained a development 
and variety of types comparable to their present condition. Out of 
some 12,000 well-established species of Fishes known to exist at 
1 The natural position of the Teleostei in the series of Fishes is indicated on 
p- 149. 
* This exists in Dapedius, as pointed out by A. S. Woodward. But this genus 
should certainly be removed from the vicinity of Lepidotus, and it seems to bear 
affinity with the Pholidophoridae. 
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