24 



FOSSIL FISHES. 



Li 



Sub-order VI. — Lepidosteoidei. 



The Lepidosteoidei are represented by the Lepidosteus, the 

 Gar-pike," or " Bony-pike " of the rivers of North and Central 

 America and Cuba : three species are living, having a completely 

 ossified skeleton, the body being covered with stout rhombic ganoid 

 scales. 



Sub-order VII. — Amioidei. 



The Amioidei are represented by the Amia, or " Bow-fin," of 

 the United States fresh-waters. 



Fig. 35.— The African Mudfish, Protopterus annectens, living in the rivers of Africa. 

 a, Represents one of the pectoral fins enlarged. 



1. There is a long series of fossil forms from the Old Bed Sand- 

 stone, and in later deposits, referred by Prof. Huxley to the 

 CrossopterygidtB — the first are known as the Holoptychiidce — having 

 large rounded bony scales deeply imbricating and sculptured on 



Fig. 36. — Holoptychius, Old Red Sandstone, Fifeshire (after Huxley), a, Paired pectoral 

 line ; b, ventral fins ; c, the anal fin ; d, anterior dorsal ; e, posterior dorsal fin. 



their exposed surfaces. The skeleton is not known ; most probably 

 it was notochordal. They only occur in the Old Bed Sandstone, 

 and are represented by the genera GJyptolepis and Holoptychius 

 (Fig. 30), from the Old Red Sandstone. (See Wall-case 5.) ' 



