480 The American Naturalist. ` [May, 
With this new information in our possession, it appears to me that 
the relations of these fishes is best expressed in the following way: 
Subclass [V.—TELEOsTOMI. 
There are four superorders of the Teleostomi or true fishes, which 
differ in the structure of the fins. 
I. Median fins each with a single bone representing axonosts. 
Paired fins unibasal ; Rhipidopterygia. 
II. Median fins with numerous axonosts. 
Paired fins with baseosts; pectorals with separate 
axonosts ; ? uni- or pluribasal ; Crossopterygia. ` 
. Paired fins with baseosts ; pectoral fins with axonosts 
and baseosts confounded ; pluribasal ; ` »  Podopterygia. 
Pectoral fins only with baseosts, these confounded 
? with an axonost, and pluribasal ; Actinopterygia. 
Rhipidopterygia. 
The orders of Rhipidopterygia are the following. They all have 
actinotrichia in place of fin-rays : 
I. Paired fins with the basilars arranged on each side of the 
median axis, or archipterygial. : 
Median fins with basilars ; Taxisha- 
II. SRANI fins with the basilars arranged fan-shaped at the end of 
shor . 
Median fins fg Pois ; Rhipidisha. 
Median fins without, caudal fins with, basila Actimsha. 
The Taxistia includes but one family, ie “Holopiyehiiaas which is 
of Devonic age. The Rhipidistia includes the Tristichopteridz, pr 
the Devonic and Carbonic; the Osteolepidæ, from the same; an 
possibly the Onychodontidz, which are Devonic ee 
The Actinistia includes the single family of the Coelacanthide, whi 
appears in the Lower Carbonic and ranges to the Upper Cretacic in 
both Europe and America. - 
The Croisi includes two orders, as follows: 
Dorsal and axonosts well developed ; actinotrichia ; 
no fin-rays ; pectorals ? unibasal ; P 
Dorsal baseosts rudimental ; fin-rays ; pectorals tribasal ; irom w 
But one family is dictated} in the Haplistia, the Tarassiide, 
Lower Carbonic of Scotland. The Cladistia are rep 
family which is not known in the fossil state, Polypteride, of OF 
io: 
