86 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



part of the pectoral, are transversely articulated, the joints being usually longer than 

 they are broad, though in some cases they are shorter. Their exposed ganoid surfaces 

 are beautifully ornamented with ridges and furrows, which in some cases are parallel 

 with their margins, in others slightly oblique ; while, as usual, small, closely-set fulcra 

 are visible along the anterior margins of the fins. 



As seen in PI. XIII, fig. 1, the scales are moderate in size compared with the bulk 

 of the fish. A flank scale from another specimen (the original type) is sb.own in fig. 9, 

 magnified three diameters, and displays a rhombic form, slightly higher than broad, the 

 anterior superior angle passing up in a sharp point, the articular peg being very 

 prominent, and the anterior covered area very narrow. The exposed area, therefore, 

 occupies nearly the entire outer surface, and is brilliantly ganoid and sculptured all over 

 by prominent, clearly cut, slightly wavy, subparallel ridges, which occasionally bifurcate 

 or are intercalated, and whose direction is obliquely downwards and backwards, ending 

 on distinct denticulations of the hinder margin, Fig. 10 shows the under surface of a 

 similar scale magnified to the same extent, and upon it there will be observed at the 

 lower margin a well-marked socket for the articular peg of the scale below, the vertical 

 keel being, however, rather feeble ; then along the posterior margin is seen a narrow 

 area crossed by short oblique grooves, which end between the denticulations of the 

 posterior margin and produce the pectinated appearance which gave occasion for the 

 specific name of the fish. In fig. 11 we have a scale from a position further back and 

 similarly magnified, and it will be seen that it follows the general rule in this family in 

 being more equilateral and more oblique; while fig. 12 shows the under surfaces of 

 two such scales, one of which is considerably lower than it is broad, wants the articular 

 peg, and probably came from near the ventral margin, its apposition with the other 

 being only accidental. In fact, the scales of E. pectinatus seem to conform to the 

 general rule in this family as to difference of form on different parts of the body. 



Observations. — The first specimen of this species which came under my observation 

 consisted of a slab with dislocated scales, which, on account of their configuration, I 

 referred to Eloniehi/iys, though at first with a query ; the subsequent discovery of the 

 general form of the fish along with other details of its structure led me then to with- 

 draw the query, and to consider that the most appropriate place for it was indeed in this 

 genus. As to its specific characters it cannot possibly be confounded with any other 

 known form, but against the generic j)Osition lo which I have assigned it might be 

 adduced the extended base of the anal fin, which is not found in any other species of 

 Monichthys. In this character it resembles the Triassic Gyrolepis, and to some extent 

 the Permian Pi/yojjferus. In Gyrolepis, however, the pectoral fins have most of their 

 rays unarticulated till towards their terminations, the operculum, though long, is 

 differently shaped, the overlapped area of the scales is broader, and according to Dames 

 the two infra-clavicular plates are fused in the middle line.^ In Pyyopterus the pectoral 

 1 Dames, " Die Ganoiden des deutschen Muschelkalks," in Dames' and Kayser's 'Palaeoiito- 



