CA TFISHES 171 
among these forms which compete most actively for 
survival. 
To conclude the present chapter, several forms of Tele- 
osts may be briefly discussed as especially characteristic 
of the group, namely the catfish, Mormyrus, eel, perch, 
cod, flounder, porcupine-fish, sea-horse. 
The catfish, representing the Sz/urvotds, has, as already 
noted, many structural affinities to the sturgeon, and is, 
perhaps, a direct descendant of some early type of Mesozoic 
Palzoniscoid. It is a representative of a large and wide- 
spread family, usually of river fishes. Its habits are slug- 
Fig. r77.— The bull-head (catfish), Amiurus melas (Raf.), Jord. and Cope- 
land. xX 4. (After GOODE in U.S. F.C.) Eastern North America. 
gish and mud-loving. Its trunk is heavy, rounded, and 
without Teleostean scales; its broad mouth margin is pro- 
vided with barbels ; the fin rays of its dorsal and pectoral 
fins fuse into a stout, serrate, erectile spine. In North 
American forms armouring derm plates are developed 
only on the head roof (Fig. 177). Closely akin to these 
are ‘the Asiatic genera, and the single European species, 
Silurus glanis, the gigantic We/s of the Danube. The. 
Nile is of interest if only for its forms of catfish to 
parallel the shapes and structures of the recent Teleosts. 
