﻿48 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



The name Monichthys was proposed by Giebel 1 for certain Fishes {E. German, 

 crassidens, and Icevis), from the Coal-measures of Wettin, near Halle, which he con- 

 sidered intermediate in generic characters between Amblypterus and Palceoniscus as 

 defined by Agassiz. According to the proposer of the genus, they resembled 

 Palceoniscus in their fulcrated fins, but differed from it in the absence of the scaly 

 covering to the rays, affirmed by Agassiz to exist in some Palceonisci ; while to certain 

 " Amblypteri " they showed an affinity in the striation of their scales and to " Amblyp- 

 erus " in general in the large size of the fins. Their special characteristics were to be 

 found in the dentition, which consisted of an external series of minute teeth, comparable 

 with the " Biirstenzahne " of "Amblypterus" between which there were larger conical 

 teeth, " wie ich dieselben weder bei den Palseonisken noch Amblypteren finde." Unfortu- 

 nately, however, for this diagnosis, the fin-rays of Palceoniscus are no more covered 

 with scales than those of any other genus belonging to this family ; nor are the fins 

 of Agassiz's " Amblypteri " destitute of fulcra " except on the upper lobe of the 

 tail," as has been so repeatedly stated by compilers, who, copying this error from the 

 " Tableau synoptique," have apparently overlooked the correction of it made by Agassiz 

 himself a few pages further on in his general description of the genus. 2 The dentition, 

 too, of Giebel's Elonichthys is essentially similar to that of Agassiz's Amblypterus 

 macropterus {Bhabdolepis, Troschel), in which large conical teeth were shown to exist by 

 Goldfuss in 1847, 3 and again by Troschel in 1857 ; 4 the latter author using this character 

 to separate the striated-scaled " Amblypteri " of Saarbriicken and Lebach, under the 

 name of Bhabdolepis (B. macropterus, B. eupteryyius), from their smooth-scaled associates 

 with minute slender teeth, for which the term Amblypterus was retained {A. latus, A. 

 lateralis) . 



An examination of the type-specimens of Monichthys in the Mineralogical Museum at 

 Halle has, however, convinced me that the genus is tenable, and that to it is referable an 

 extensive series of Palceoniscidce, which will include, besides several new species, various 

 forms referred by Agassiz and other writers to Amblypterus, Palceoniscus, and Pyyo- 

 pterus. Several species, also, whose position from want of sufficient information is some- 

 what doubtful, may best be placed here provisionally. 



Though closely resembling Bhabdolepis, it differs in the absence of the subopercular 

 plate ; the operculum is also usually more largely developed ; while from Amblypterus, 

 as restricted by Troschel, the dentition and the greater obliquity of the suspensorium 

 are obvious marks of distinction. From Palceoniscus, to which some of the species 

 {E. Bobisoni, striolatus, Egertoni) were referred by Agassiz, it is distinguished by the 

 large size of the fins, and by the possession of large conical teeth in the jaws. Nearly 



1 ' Fauna der Vorwelt,' i, 3, p. 249. 



2 ' Poissons Fossiles,' ii, pt. 1, p. 29. 



3 ' Beitrage zur vorweltlichen Fauna des Steinkohlengebirges,' p. 20. 



4 'Verh. des naturh. Ver. des preussischen Rheinlandes,' XIV, p. 12. 



