470 woodward: fossil fishes of the upper lias of WHITBY. 
superficial points or granules of ganoine well known on the 
pectoral fin of Chondrosteus. 
No scales or dermal plates have been observed among the 
remains of Gyrosteus^ and the body wa? thus probably naked, 
as in Chondrosteus. It is indeed strange that no traces have 
hitherto been found of the lozenge-shaped scales which invest 
Fig. 12. — GyrosteAis mirahilis, Ag., MS.; fragment of caudal fin, one-third 
nat. size. [Brit. Mus., No. P. 3356c.] 
the upper lobe of the tail in all known sturgeon-like fishes, 
recent and extinct ; but the upper border of the tail is ridged 
in the usual manner by a row of great saddle-shaped, over- 
lapping scutes, which form a serried armour. Two small 
examples of these scutes are preserved in Mr. Chad wick's 
