54 THE VICTORIAN NATURALIST. 



series, but still pass conformably into the lower bed from which 

 Mr. Cresswell and himself obtained the fish remains in situ. 



The collection of fishes has, in the main, a distinctly Devonian 

 fades, but still with a strong similarity to Lower Carboniferous in 

 some forms. All the species are new, and figures have been 

 prepared for publication. The most common fossil is that men- 

 tioned as so like Gyracanthns, but having no denticles on the 

 two posterior ridges. Professor M'Coy proposes for it the generic 

 name Gyracanthides. It presents so many variations of form as 

 to suggest many spines on different parts of the body, as in some 

 bony fishes, rather than the one or two bony spines in front of 

 the dorsal fins of sharks. The Gyracanthides are also associated 

 with many large bones of the head of true bony fishes, but may 

 not belong to the same creature for all that. The next most 

 common and striking fossil of these beds is a large scale, with the 

 radiating cellular internal structure very nearly of the Upper 

 Devonian Glyptolepis, and about the size and shape of the well- 

 known Upper Old Red Sandstone Glyptolepis leptopterus. Scales 

 of this general type are common in Devonian rocks of many 

 countries, but unknown. in Carboniferous strata. 



The next most abundant fishes are large forms of the family 

 Palasoniscidse, most closely related to the genus Cosmoptychius, 

 of Traquair, exceeding in size the C. striatus, from the Calciferous 

 Sandstone series from Craigleith and other Scotch localities, at 

 the very base of the Carboniferous series. The Mansfield fishes 

 constitute three or four species of a distinct genus, for which he 

 proposes the name Cosmolepides, naming the largest and most 

 abundant C. sweeti (M'Coy), after the discoverer. This will also 

 be figured in the forthcoming decades. 



The next group of fishes were all collected by Mr. Sweet's 

 party, are species of the family Acanthodidae, so strikingly 

 abundant in the Devonian rocks of Scotland, Russia, and 

 America, although some degenerate examples also enter into the 

 Carboniferous. The Mansfield specimens are most nearly related 

 to the Diplacanthi of the Old Red Sandstone of Scotland, but 

 form a distinct generic type, of which figures have been prepared. 

 The chief type is nearly related to Diplacanthus, and is named 

 Chi?-aropalus langtrei (M'Coy). Some imperfect remains are 

 probably related to Chirolepis, but with the lateral line so greatly 

 developed and bordered with two rows of greatly enlarged scales, 

 that he has no doubt the generic type should be separated from 

 all those known, and he has named it Eupleurogmus cresswelli 

 (M'Coy), after Rev. Mr. Cresswell, who found the only known 

 fragments. 



Associated with the last-named fish some examples of the 

 greatest interest — namely, shields of fishes of the group Pteraspidas 

 (Heterostraci of Ray Lankester) — have been found; these are 



