580 SYSTEMATIC RELATIONS OF FISHES. 
Having instituted an investigation of Agassiz’ Ganoids, in an 
able memoir he purged it of the Plectognath and Lophobranchiate 
divisions, which are obviously not related to it. These with the 
Malacopterygians and Acanthopterygians, he erected into a sixth 
sub-class, the Teleostei. This sub-class containing the greater 
part of existing fishes, embraced six orders, viz.: -Acanthopteri 
(Cuvier’s Acanthopterygians), Anacanthini (new, for the Cod 
family, ete.) ; Pharyngognathi (new, for fishes with connate infe- 
rior pharyngeal bones) ; Physostomi (Malacopterygians of Cuvier, 
nearly); Plectognathi and Lophobranchii of Cuvier. The great 
number of facts in the anatomy of fishes added by Müller, consti- 
tute him the father of modern ichthyology. 
Professor Gill, in 1861, adopted many of the divisions of Müller, 
and rejected some; others were newly proposed. But four sub- 
classes were recognized, the Dermopteri, which includes also 
Müller’s Leptocardii; the Elasmobranchii, equivalent to Müller's 
Selachii; the Ganoidii, including here Miiller’s Dipnoi; and the 
Teleostei. Six orders were attributed to the last sub-class, which 
were quite different from those of Miiller. 
Subsequent to this publication, important contributions to the 
system have been made by Kner, Lütken, Gill, Huxley, etc., which 
will be noticed at the proper time. 
The writer having been engaged in an examination of the oste- 
ology of the bony fishes, and general anatomical studies of the 
whole, has proposed to point out some further modifications of the 
received system, which he believes will render it a closer reflection 
of nature. There are some portions of the skeleton which have 
been to a great extent overlooked in seeking for indications of 
likeness and difference of types, and the estimation in which many 
known characters are held, may be much altered on the study of 
extended material. The skeletons on which the present study is 
made, are one thousand in number, two hundred belonging to the 
_ Academy of Natural Sciences of Philadelphia, and eight hundred 
to the writer, being the collection made by Professor Joseph Hyrtl, 
the distinguished anatomist of Vienna. This collection has been 
long known to anatomists in Europe as the most beautifully and 
reliably prepared in existence, and as valuable as any for study, 
on account of the fulness of the representation of the various 
types. 
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