AND ON THE CLASSIFICATION OF FISH. 533 
ventral fins, when present, are attached to the thorax or throat. 
Partly Cuvier’s Malacopterygii subbrachii and partly Malaco- 
pterygii apodes. 
Families: Gadoidei, Ophidini, Pleuronectides. 
The Pharyngognathi* comprise the Acanthopterygians and 
the Malacopterygians, which have the lower hyoid bones united. 
Their ventral fins are partly situated on the thorax, partly on 
the abdomen. The swimming-bladder is always closed, and un- 
provided with an air-tube. 
Families: Labroidei cycloidei, Mill. Labroidei ctenoidei, Miill. 
Chromides, Mill. Scomberesoces, Mill. 
The Physostomi are composed of Malacopterygii; the ventral 
fins when present are always abdominal: they are the only ones 
in this subclass the swimming-bladder of which constantly pos- 
sesses an air-duct. They may be arranged into two suborders, 
which nearly correspond to Cuvier’s Malacopterygii abdomi- 
nales and Malacopterygii apodes. 
To the Physostomi abdominales belong the families Siluroidei, 
Cuy. Cyprinoidei, Ag. Characinit, Mill. Cyprinodontes, Ag. 
Mormyri, Cuv. Esoces, Mill. Galaxie, Mull. Salmones, 
Milt. Scopelini§, Mill. Clupeide, Cuv. Heteropygii||, Tellk. 
( Amblyopsis.) 
To the Physostomi apodes s. Anguillares belong the families 
Murenoidei, Mill. Symbranchii, Mull. Gymnotini, Mull. 
In the family of the Siluroidei, Cuv., I separate as groups the 
true Stluroidei or Siluri, and the Goniodontes, Agass,, or Lori- 
carini. The family of the Cyprinodontes, Ag., or Pecilie, Val., 
which I have elsewhere characterised, contains only such fishes 
as have a protractile mouth, and which is bounded solely by 
the intermaxillary bone. The genus Umbra, Cramer (Cyprino- 
don umbra, Cuv., Umbra Crameri, Nob.), does not belong to the 
Peecilian genus Cyprinodon, Val.: in addition to the intermax- 
illary teeth, it has teeth in the vomer and palate-bones; the 
mouth is bounded anteriorly by the intermaxillary bone, ex- 
ternally by the upper jaw, as in sox, with which also it agrees, 
in the stomach not having any blind sac, and in the intestine and 
their covered pseudo-branchie. sox and Cyprinodon are the 
only two genera now certainly belonging to the Esoces. 
Through the kindness of M. Valenciennes I have been able 
® Loe. cit., p. 805. + Ibid. p. 313. t Ibid. p. 323. 
§ Ibid. p. 321. || Mull. Archiv, 1844, p. 392. 
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