558 RAMSAY H. TRAOJTAIR ON AMBLYPTERUS, 



Carboniferous Palceonisci all belong to types essentially distinct 

 from that of P. Freieslebeni. 



II. Type of Pcdceoniscus Duvernoyi, Ag. (Genus Amblypterus, Ag.). 

 This includes fishes with mostly rather deep bodies arcuated in 

 front of the dorsal fin, which is situated rather further back than in 

 the true Palceonisci ; the median fins are large ; the tail large and 

 powerful ; the scales usually smooth ; the suspensorium only 

 slightly oblique ; the teeth probably very minute. There must be 

 included (besides the Agassizian species P. Duvernoyi, ivratislaviensis, 

 and lepidurus), the P. dimidiatus, elongcttus, tenuicauda, gibbus, and 

 opisthopterus of Troschel, the P. Gelberti of Goldfuss, the P. decorus, 

 arcuatus, and Beaumonti of Egerton, and, I think, also the P. 

 Bohanni, caudatus, obliquus, Beussii, and luridus of Heckel. P. 

 minutus, angustus, Voltzii, and Blainvillei of Agassiz seem to be 

 allied forms, though the latter especially may possibly be the type 

 of still another genus. 



Between these species and the smooth-scaled Amblypteri of 

 Saarbriicken and Lebach I can, as already stated, see no tangible 

 grounds of generic distinction, though in some (e. g. P. decorus) the 

 fins are rather smaller and their fulcra more prominent. But the 

 slight obliquity of the suspensorium, the general form of the body, 

 the position of the fins, and the aspect of the squamation are 

 similar in all. As regards the scales, they are mostly smooth, or 

 show only slight concentric lines ; in some, however (e. g. P. 

 Gelberti, P. Beaumonti), those of the front of the flank display a 

 certain amount of ornamentation. They are certainly not Palceo- 

 nisci in the strict sense of the term : and until at least their cranial 

 structure and dentition are more fully elucidated, they are better 

 classed with Amblypterus than with any other genus. Giebel had, 

 indeed, previously proposed to transfer P. Duvernoyi to Amblypterus, 

 but, unfortunately, on the untenable ground that the fulcra were 

 absent in it except on the upper lobe of the tail. 



All these species are from strata similar in age to the beds at 

 Saarbriicken &c.,in which the typical Amblypteri occur, and which are 

 now referred by continental geologists to the Lower Permian {unteres 

 Rothliegendes). .Even the fish-bearing schists of Autun, characterized 

 by Palceoniscus Blainvillei, have ceased to be reckoned as apper- 

 taining to the ' Terrain houiller.' 



III. Type of P. striolatus, Ag. (Genus Elonichthys, Giebel). 

 Here are included P. striolatus, Bobisoni, and Egertoni, fishes with 

 large median fins, sculptured scales, powerful tail, very oblique 

 suspensorium, and, as regards the dentition, possessed of a row of 

 distinct conical laniaries internal to a series of smaller teeth. It is 

 difficult to conceive why Agassiz placed these species in the genus 

 Palceoniscus, while at the same time he described, as has been 

 already shown, certain closely allied forms from the AVardie shales 

 as Amblypteri. They are all, in my opinion, referable to the genus 

 Elonichthys of Giebel. (See also under type of Amblypterus nemo- 

 pterus, p. 553.) 



IV. Type of Palceoniscus ornatissimus, Ag. (Genus Bhadinichthys, 



