of Edinburgh , Session 1S7C—77 . 43 1 
tainty as to the genus to which it belongs. Meanwhile, I have 
assigned this species to Elonichthys on account of the general con- 
figuration of the scales. Should this opinion prove correct, it is 
certainly the largest species of the genus hitherto described. 
Geological Position and Localities. — In the hlackband ironstone 
of Gilmerton belonging to the Lower Carboniferous Limestone 
series ; in bituminous shale from a similar horizon at Carluke, in 
the collections of Dr Rankin of Carluke, and Mr Grossart of Sals- 
burgh ; in calcareous shale accompanying the limestone of Levenseat 
in the Upper Carboniferous Limestone group. I am indebted to 
Mr Grossart for specimens from the last-named locality. 
Rhadinichthys, gen. nov. Traquair. 
Palceoniscus (pars), Agassiz. 
Body more or less elongated ; scales moderate, sometimes rather 
large, variously ornamented or nearly smooth, their posterior margins 
serrated. Caudal body prolongation slender. Dorsal fin placed 
rather far back, commencing only very slightly in front of the anal ; 
the principal rays of the pectoral unarticulated till towards their 
terminations. Suspensorium very oblique ; gape very wide ; jaws 
armed with a row of incurved conical laniaries, outside which there 
is a series of smaller teeth. 
I propose to institute the genus Rhadinichthys (paotvo?, slender, and 
for the Palceoniscus ornatissimus of Agassiz, and a number of 
other species from carboniferous rocks, many of which have hitherto 
been undescribed. These fishes differ markedly from Palceoniscus 
in the structure of the pectoral and in the position of the dorsal fin, 
in these respects approaching Pygopterus, from which they are, 
however, distinguished by their scales being proportionally larger 
and thicker, the anal n not being prolonged backwards in a fringe- 
like manner, and the caudal body prolongation being much less 
powerful. Rone of the species of Rhadinichthys attain large dimen- 
sions ; most of them are, indeed, fishes of very small size. 
This genus is, so far as is yet known, confined to the carboni- 
ferous formation, and is abundantly represented in rocks of that age 
in Great Britain. Judging from the figures given, Palceoniscus 
Oairnsii of Jackson, and some of the other small Pakeoniscidae from 
