98 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



of the previous species, somewhat deeply fusiform, with the dorsal fin placed rather far 

 l>aek — so far back, indeed, as to appear almost opposite the anal, but that is no doubt 

 the posterior position slightly exaggerated by distortion. 



The external cranial bones display a rugose sculpture, but in no specimen are they 

 well shown, being always more or less crushed and broken. So arc likewise the facial 

 bones, with the exception of the maxilla and mandible, which can often be recognised 

 both in situ and in an isolated condition. A typical isolated maxilla is shown in PI. 

 XX, fig. 11, and is seen to be markedly different in its contour from that of G. punc- 

 tafus (PI. XIX, fig. 2), inasmuch as the dentary margin is pretty sharply bent downwards 

 just behind the origin of the sub-orbital process from the post-orbital plate, which latter 

 part appears proportionally high from above downwards, short from before backwards. 

 Its external surface is marked with closely set ridges which run mainly parallel with the 

 anterior, posterior, and inferior margins of the bone. The dentary element of the 

 mandible seen from the outer surface is represented in fig. 12, and is seen to be some- 

 what stouter than the corresponding bone in G. punctatus ; its ornament consists of 

 ridges, which in the middle run straight backwards and forwards, forming a longitudinal 

 band, above which they run obliquely upwards and forwards, and below which and along 

 the inferior margin they are slightly contorted. The configuration of the teeth is essen- 

 tially the same as in the previous species, though they are larger in size, a little more 

 clumsy in shape (figs. 13 and 14), and not quite so regular in arrangement. The 

 scales are proportionally considerably larger than in G. punctalus, except on the 

 caudal body-prolongation, where they are equally small. Their outer and brilliantly 

 polished free surfaces (fig. 10) display a number of delicate punctures, and occasionally, 

 though indeed seldom, a few traces of striation along the anterior and inferior borders ; 

 the posterior margins of the flank scales are finely denticulated. The form and position 

 of the fins are as in the Wardie species, though their rays are slightly coarser and fewer 

 in number, though it is difficult to ascertain with accuracy their numbers in the various 

 fins. The articulations of the rays are also a little closer, but the configuration of the 

 joints is the same, these being scale-like, emarginate distally, convex proximally, and with 

 a little furrow parallel with their anterior and posterior margins. 



Geological Position and Localities. — From the Lower Carboniferous Rocks of the 

 central valley of Scotland, but occurring at a higher horizon than is the case with G. 

 punctatus. The Royal Scottish Museum contains a couple of imperfect specimens from 

 the Dunnet Shale at Straiton, Midlothian (Calciferous Sandstone Series) ; all the other 

 known specimens are from the Gilmerton Ironstone, a member of the Lower Limestone 

 Series formerly worked at Venturefair Pit, Gilmerton. The types are in the Royal 

 Scottish Museum and in the Collection of the Author. 



