12C) GANOID FISHES OP THE CARBONIFEROUS FORMATION. 



the same time the cliliercnces between it and Cijchplyduus carbonarius arc a})|)areiit at 

 the first glance. In C. carbonarius the ridges on tlie scales are ninch finer, the one along 

 the posterior margin being also more or less zigzagged in contonr, while there is not that 

 difference in the sctdptnre of the scales along the back, which is so prominent a 

 character in C. conccnfricas. The sha|)c of the flank-scales also differs to a considerable 

 extent; for while in the former species the postero-inferior angles arc sim[)ly ronnded 

 off, in C. concentricns they are absolntely obtnse, so that the inferior margin looks as 

 mnch backwards as downwards. 



Geological Position and Locality. — A Lower Carboniferons fish, and as yet oidy 

 known from the Calciferous Sandstone Series at (jilcncartholm, Eskdale. 



The type is in the Collection of the Geological Snrvey of Scotland. 



Genus — RnADiNiCHTHYS, 'Traquair, 1877. 

 Pal.eoniscus (pars), Agassiz. 



Generic Cliaraclers. — Body fusiform, often elongate-fusiform ; caudal body-prolonga- 

 tion usually weak ; botly-scales rhond)ic, usually, but not always, denticulated 

 posteriorly, their overlaj)ped surface narrow. Principal rays of pectoral fin unarticulated 

 till towards their terminations; dorsal situated rather far back, commencing only 

 slightly in front of the anal, sometimes indeed directly opposed to the anal; caudal 

 deeply cleft and ineqnilobate. Suspensoriuni very obli(pie, gnpe laigc ; operculum 

 oblong ; suboperculum quadrate ; branchiostegal rays or plates numerous, with a 

 median lozenge-shaped plate behind the symphysis of the mandible as in Elonicht/iys, 

 Gonatodus, etc. Jaws armed with a set of incurved conical laniaries, outside which 

 there is a series of smaller teeth. 



lleinarks. — I proposed this genus in 1877 for the reception of the "Palaoniscus" 

 ornatissimus and F. earinatus of Agassiz, which, on account of the condition of the 

 pectoral fin-rays and the backward position of the dorsal fin, could not be included either 

 in that genus or in Eloniclitliys. As referable to the same category I also noted 

 " Palaoniscus" JFardi (Ward) from the British Upper Carboniferous, and ^'Palaotiiscus'' 

 Cairnsi and Alberti of Jackson from the Lower Carboniferons of New Brunswick, while 

 in the year after I also added "Palaoniscus " inonensis of Egerton to the new gemis. 

 The number of species referred to lUadinicht/iys has since those days been on the 

 increase. No less than twenty-six names of species, including synonyms, are enumerated 

 by Dr. Smith Woodward in his Catalogue (Ft. ii, 1891), of which five are from the 

 American continent. More recently "Palaoniscm" demnicm of Clarke has been added 

 to Uhadinicklhys by Eastman, who has likewise described a new species also from the 

 American Upper Devonian, to which he has given the name of Rhadinichthjs Beani} 

 This species is remarkable as having furnished a number of heads in which the form of 

 1 EastiiKin, 'Geo). Survey, Iowa,' vol. xviii, 1908, pp, 258 GO, and 264-272. 



