30 moCKEDlNGS OF THE 



closely those of an aniphibianliinb than the fin-structures of any 

 otheT known fishes. Interesting sugi^iestions as to their possible 

 homolo;;ies have been made*, and we may eventually discover the 

 actual links among the Lower Carboniferous Stegocephala, of 

 wliich only unsatisfactory fragments of the limbs have hitherto 

 been seen. 



It is reasonable to suppose that at tlie time when the Ampliibia 

 originated, there were among the fishes other abortive groups 

 besides the ordinary Dipnoi wliich approached the higher grade. 

 Among these 1 have long placed the curious armoured Devonian 

 fishes which are now generally known as Arthrodira f. I have, 



Fiff. 2. 



Crushed remains of the paljite of Kusthenopteron foordi, from the Upper 

 Devonian of Scaiimenac Bay. Canada, one-half nat. size. The shape of 

 the cranial roof, preserved on the opposite side of the slab, is shown in 

 dotted outline, be. basieranial axis with hollowed hinder end ; ccpt. eeto- 

 pterygoid ; enpt. entopterygoid ; rapt, metaptervgoid ; pal. ])alatine ; 

 qu. quadrate ; vu. vomer. (Brit. Mas. no. P. fi807.) 



indeed, hitherto followed Xewberry in regarding them as aberrant 

 Dipnoi, but new fossils have convinced me that they belong to a 

 distinct group and have not nn autostylic skull. 



The general appearance of the skeleton in the Arthrodira is 

 best known from the specimens of a small species of Coccosfens 

 (Hg. 4 A) found in the Old Red Sandstone of Northern Scotland. 

 The head is completely encased in bony plates, and the jaws 



* W. K. Gregory, Ann. New York Acad. Sci. vol. xxvi. (li)15), pp. 353-3(i9, 

 pi. iv. 



t A. S. Woodward, Catal. Foss. Fishes Brit. Mus. pt. ii. (1891), pp. 276-316, 

 pis. vii., viii. ; L. Hussakof, Mem. Amer. Mus. Nat. Hist. vol. ix. (1906), 

 pp. 150-154, pis. lii., xiii. 



