278 Proceedings of the Royal Society 
these forms are so close that it seems almost unaccountable that 
they should have been placed by Agassiz in different genera ; his 
having done so seems, indeed, to indicate the arbitrary nature of the 
distinction which he drew between Amblypterus and Palceoniscus , 
as well as his not having fully realised the nature of the essentially 
distinctive characters of the true Pygopteri. 
Amblypterus Portlockii of Sir Philip Grrey-Egerton * seems to 
belong to this genus, as probably also does Palceoniscus Brownii of 
Jackson, judging from the figure given. f The same must also be 
said of P. peltigerus of Newberry, | which was indeed first described 
by that author as an Elonichthys .§ 
As above defined, Elonichthys is pre-eminently a carboniferous 
genus, and well represented in strata of that age in G-reat Britain 
and other countries. The necessary restriction of the limits of the 
genera Palcecniscus, Amblypterus , and PygopteruSj and the transfer- 
ence of the carboniferous species formerly referred to them to 
Elonichthys and other genera (Nematopty chius, Rhadinichthys ) leave 
the three first named without representatives in the carboniferous 
formation, so far as our present knowledge goes, — a conclusion which 
may appear at first somewhat startling to geologists, who have 
been so long accustomed to look upon them as characteristic of that 
era, as well as of the succeeding Permian. |] 
Elonichthys nemopterus , Agass. sp. 
Amblypterus nemopterus, Agassiz, Poissons Foss. vol. ii. p. 1 p. 107; 
Atlas, vol. ii. pi. 46, figs. 1 and 2. 
To Sir Walter C. Trevelyan, Bart., of Wallington, Northumber- 
land, I am indebted for the loan of the original example of this 
species figured by Agassiz ; the only other specimen, which I can 
with certainty identify with it, is contained in my n collection. 
Its principal specific characters may be summed up as follows : — 
Length from 4 to 5 inches ; scales rather small, their posterior 
* Quar. Jour. Geol. Soc. vi. 1850, p. 2. 
t Report on the Altert Coal Mine, New Brunswick, ‘p. 52, pi. i. fig. 2. 
J Geol. Survey of Ohio, Palaeontology, vol. i. p. 345, pi. xxxviii. fig. 1. 
§ Proc. Acad. Nat. Sc. Philad., 1856 ; pp. 96-100. 
|| The strata at Saarbriicken and Lebach, containing the typical Amblypteri, 
as well as the fish-bearing beds of Munster- Appel, Kreuznach, Goldlauter, &c., 
in Germany, and of Autun in France, long believed to belong to the carboni- 
ferous formation, are now referred by continental geologists to the Lower Per- 
mian (“unteres Rothliegendes ”). 
