418 Dr. A. S. Woodward on Myriolepis liibeniica. 



llie dorsal fin only a fragment remains, but enou^ih is 

 preserved to show that it arises at least as far forwards as 

 the pelvic fins. The anal fin is also incomplete, but there are 

 some good impressions of the long axonosts and short baseosts 

 which support it. The caudal fin is deeply forked and some 

 of its stout rays are ornamented with delicate longitudinal 

 striae like those of the pelvic fin already mentioned. 



The characteristically small scales covering the whole of 

 the trunk are well indicated, but it is not clear whether those 

 of the flank are deeper than broad. At some points near the 

 dorsal and ventral borders of the fish the scales are clearly 

 equilateral. The whole squamation is ornamented wirii 

 delicate closely arranged ridges, which sometimes bifurcate, 

 are sometimes subdivided into elongated tubercles, and are 

 all disposed in an antero-posterior or horizontal direction 

 (fig. la). The course of the lateral line is marked by a 

 simple ridge. On the upper caudal lobe, which is broken 

 away distally, the scales are relatively larger and oat-shaperl ; 

 but they seem to be preserved only as impressions of the 

 inner face. 



Adding the new facts now discovered to those previously 

 ascertained, M. hibemica may be briefly diagnose 1 as 

 follows : — 



A stout species attaining a length of about 30 cm. Length 

 of head with oi)ercular apparatus considerably less than the 

 maximum depth of the trunk, and contained somewhat more 

 than four times in the total length of the fish. Cranial roof 

 coarsely tuberculated ; mandible longitudinally striated ; 

 bones of pectoral arch concentrically striated. Pelvic fins 

 nearly as large as the pectorals, which, when adpressed to the 

 trunk, reach the former; dorsal fin arising opposite the origin 

 ot the pelvic pair; anal fin extending back almost as far as 

 the caudal ; fin-rays ornamented with fine longitudinal 

 striations. Scales ornamented with close and delicate trans- 

 verse ridges, which sometimes bifurcate and are sometimes 

 subdivided into elongated tubercles. 



There is still nothing to prevent this fish of the Irish Coal- 

 pleasures from being assigned to the same genus as the 

 Australian Triassic and Permo-Carboniferous fishes, for which 

 the name Mi/riolepis was originally proposed, although, as 

 remarked by Dr. Traquair, the exact nature of the pectoral 

 fin in the tyj.ieal species remains unknown. The above 

 specific diagnosis, however, readily distinguishes d/. hiher- 

 nicd, which is remarkable for the stoutness and shortness 

 of its abdominal region and for the forward position of the 

 dorsal fin. 



