﻿PLATE XI. 



Fig. Page 



1 a-d. Holoptychius flemingi, Ag. ; scales, external aspect, two 

 from the abdominal, and two from the caudal region. — 

 Upper Old Red Sandstone ; Dura Den. [26120 a.] 329 



2. Holoptychius (Glyptolepis) leptopterus, Ag. ; lateral aspect. 



— Lower Old Red Sandstone ; Gamrie. [P. 4042.] 334 



