2 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 18, 



six variations in the sculpture of the enamel. In five of these the 

 scale is divided by a diagonal line extending from the upper anterior 

 to the lower posterior angle, of various degrees of curvature. The 

 scale is traversed by from twenty to four-and-twenty strise ; those, 

 on one half of the scale, sometimes the upper, sometimes the lower, 

 run parallel to the diagonal line ; those on the other impinge on it at 

 various angles. The sixth variety has a raised ridge in place of the 

 diagonal line to which the striae converge on either side. The latter 

 form of scale occurs behind the pectoral fins. He describes the head 

 bones as ornamented with granules, closely arranged in radiating 

 lines. The teeth he affirms to be strong and conical {kegelformig), 

 not en brosse as stated by Agassiz*. 



{Neiv Species.) 

 Amblypterus Portlocki, Egerton. 



Colonel Portlock, in his ' Report on the Geology of the County of 

 Londonderry, and of parts of Tyrone and Fermanaghf ,' mentions 

 some scales as probably belonging to this genus, found in the coal 

 shale of Ballycastle, in the clay and marl of Moyola hi the parish of 

 Maghera, and in Fermanagh. I have two specimens, one from 

 Moyheeland near Draperstown, the other from Maghera, apparently 

 belonging to the same species, which being new, I propose to desig- 

 nate by the name of the discoverer. The specimens are very imper- 

 fect, but the character of the scales is sufficient to distinguish the 

 species from those hitherto known. The specimen from Moyheeland 

 shows the insertion of the pectoral fin, and a portion of the humerus. 

 The surface of the latter is covered with broad flattened plicse running 

 nearly parallel with the curvature of the bone. The rays of the fin 

 are strong, and appear to have been less numerous than is generally the 

 case in this genus. The scales are large for the size of the fish. 

 They are very thick, and are ornamented on the entire surface with 

 strong prominent ridges, fewer in number and coarser than in any 

 other Amblypterus, so much so that a single scale is quite enough to 

 indicate the species. 



Genus Eurynotus, Ag. 



This genus was arranged by Agassiz between the genera Palceoniscus 

 and Platysomus, and was considered to have affinities to the latter 

 genus and AmhlypterusX' In consequence of the discovery of the 

 dentition of Platysomus and its removal to the family of the Pycno- 

 dontidce, it was necessary to inquire into the propriety of retaining 

 Eurynotus in the position originally assigned to it. This examination 

 became more necessary in consequence of a letter received not long 

 ago from Mr. Hugh jMiller, communicating the discovery of a group 

 of rounded palatal teeth in a specimen of Eurynotus crenatus found 

 in the neighbourhood of Crail in Fifeshire. I have since received a 

 very accurate cast of this specimen showing the teeth in situ. These 

 at first sight would seem to indicate a Pycnodont, but a comparison 



* Poiss. Foss. vol. ii. p. 30. f Page 462. { Poiss. Foss. vol. ii. p. 153. 



