Io The Ganoids 
“Tt has been objected that the Ganoids do not constitute 
a natural group, and that the characters (i.e., chiasma of optic 
nerves and multivalvular bulbus arteriosus) alleged by Muller 
to be peculiar to the teleostomous forms combined therein are 
problematical, and only znferentially supposed to be common 
to the extinct Ganoids so called, and, finally, such objections 
couched in too strong language have culminated in the assertion 
that the characters in question are actually shared by other 
physostome fishes. 
“No demonstration, however, has been presented as yet 
that any physostome fishes do really have the optic chiasma 
and multivalvular bulbs arteriosus, and the statement to the 
contrary seems to have been the result of a venial misappre- 
hension of Prof. Kner’s statements, or the offspring of impressions 
left on the memory by his assertions, in forgetfulness of his 
exact words. 
“But Prof. Kner, in respect to the anatomical characters 
referred to, merely objects: (1) that they are problematical, 
are not confirmable for the extinct types, and were probably 
not existent in certain forms that have been referred to the 
Ganoids; (2) the difference in number of the valves of the 
bulbus arteriosus among recent Ganoids is so great as to show 
the unreliability of the character; (3) a spiral valve is developed 
in the intestine of several osseous fishes (‘genera of the so-called 
intermediate clupeoid groups’), as well as in Ganoids; and 
(4) the chiasma of the optic nerves in no wise furnishes a posi- 
tive character for the Ganoids. 
“It will be noticed that all these objections (save in the 
case of the intestinal spiral valve) are hypothetical and vague. 
The failure of the intestinal spiral valve, as a diagnostic char- 
acter, has long been conceded, and in this case only have the 
forms that prove the failure been referred to; in the other cases, 
where it would be especially desirable to have indicated the 
actual types falsifying the universality or exclusiveness of 
the characters, they have not been referred to, and the objec- 
tions must be met as if they were not known to exist. 
“(1) The characters in question are, in the sense used, 
problematical, inasmuch as no examination can be made of 
the soft parts of extinct forms, but with equal force may it be 
