REPORT ON FOSSIL FISHES. ol 
The ‘pectoral fin is scarcely more than half the length of the head; its 
principal rays are unarticulated till towards their terminations. The situation 
of the ventrals is indicated by a few stumps of rays at a point a little behind 
the middle point between the pectorals and the anal. The dorsal is situated 
far back, being nearly exactly opposite the anal; both of these fins are similar 
in appearance, being moderate in size, triangular, acuminate, and slightly cut 
out behind; their rays are of medium coarseness, smooth, dichotomising 
towards their extremities, and having their articulations somewhat distant. 
The caudal is well developed, heterocercal, deeply cleft, the rays similar in 
appearance to those of the dorsal and anal; in the lower lobe dichotomising 
towards their extremities, in the upper towards the middle. Traces of well 
developed fulcra are seen along the fin margins. 
Remarks.—The position of the above described species in the genus 
Rhadinichthys is indicated by the structure of the pectoral fin, by the shape of 
the scales and the nature of their sculpture, and by its general form and pro- 
portions, although the dorsal fin is placed still further back than is usual in 
Rhadinichthys, its position being hardly if at all in advance of the anal. This 
latter character allies it to Cycloptychius, but the peculiar form of scale with 
the posterior inferior angle rounded off, and which constitutes one of the main 
diagnostic marks of the last named genus, is here absent. Its main specific 
characters—the tuberculation of the cranial shield, the peculiar sculpture of 
the mandible, and the non-denticulation of the posterior margins of the scales 
taken along with its size and proportions—are so exceedingly well marked, 
that it may at once be identified even from small fragments. 
I have pleasure in naming this new species after Mr ArrHur MAcconocuiE, 
Fossil Collector to the Scottish Geological Survey, to whose industry in his 
department is due the discovery of the rich deposits of new fishes and crustacea 
in the Lower Carboniferous rocks of Eskdale and Liddisdale. 
Position and Locahty.—Near Glencartholm, Eskdale, in the Cement-stone 
group of the Calciferous Sandstone series. 
Rhadinichthys tuberculatus, sp. nov. Traquair. 
Pl. IV. figs. 1--3. 
Description. —The length of the only entire specimen which has occurred, 
is 7 inches from the tip of the snout to the bifurcation of the caudal fin; the 
extremity of the upper lobe of the tail is not preserved, otherwise the total 
length of the fish would probably be, at least, 84 inches. The length of the 
head is 2 inches, equalling the greatest depth of the body just in front of the 
ventral fins, and being contained little more than three times in the length of the 
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