BONY FISHES AND GANOIDS. 



475 



Fig. 11.- 



-Angler Fish (JjOiphius 

 piscatorius). 



ported by a prolongation of some of the bones of the internal skeleton. The 

 teeth are rasp-like or villous, and there is no connection between the preo- 

 percular and the orbit. The apertures of the gills are very minute, and 

 situated near the root of the pelvic fins, the gills varying from two-and-a- 

 haK to three-and-a-half in number, 

 and false gills being usually absent. 

 The family has an almost cosmopolitan 

 distribution, and all its members are 

 but poor swimmers, those which are 

 of pelagic habits drifting about attached 

 to floating bodies, while the littoral 

 forms cling to submarine bodies by 

 means of their pectoral fins, which 

 serve the function of arms. The great 

 size of the wide, flat, and rounded head, 

 which carries the small eyes near the 

 middle of the upper surface, the capa- 

 cious mouth, and the modification of 

 the first three dorsal spines into tentacles, serve to distinguish the species of 

 the typical genus Lophius, which are not numerous. Rarely the common 

 British species, which is often known as the fishing-frog, grows to five feet, 

 although its ordinary length does not exceed three. The first tentacle bears 

 a filamentous appendage, which by its movement serves to attract prey 

 within reach of the capacious jaws. Another interesting member of the 

 family is the pelagic tentacle-fish — Antennarias — often found in the gulf- 

 weed, and remarkable for building a silken nest attached to the weed for the 

 reception of the eggs, which are suspended within their receptacle in a 

 cluster, like a bunch of grapes. Even more curious are the two Atlantic 

 species of Melanocetus,vrhioh are small fishes, looking as if they consisted 

 mainly of jaws and stomach. 



The Gottidce, of which the best known representatives are the mostly fresh- 

 water bull-heads (Cottus) of the Northern Hemisphere and the marine- 

 gurnards (Trigla), are well characterised by the presence of 

 a bony stay connecting the preopercular with the suborbital Family Cottidm. 

 ring of bones ; a feature found among the preceding families 

 of the section only in Pseudochromis and some allied genera. These 

 fishes have the body lengthened, and more or less nearly cylindrical ; the 

 mouth being transverse, and bearing feeble teeth generally arranged in bands. 



Whereas in some forms the skin is 

 naked, in others it is scaled, and the 

 armature may consist of a single row 

 of plate-like scales. Generally the 

 dorsal fin is divided, when the soft 

 portion — which is elongated like the 

 anal — exceeds the spinous in extent. 

 The number of rays in the theoracically- 

 placed pelvics never exceeds five ; and 

 in some cases the pectorals have fila- 

 mentous prolongations. The bull-heads, which comprise a very large number 

 of species, a few of which are marine, are noted for their habit of lying 

 sluggishly in the beds of rivers, with their heads concealed beneath the 

 pebbles. The elongated and finger-like three anterior pectoral rays serve to^ 



Kg, 12. —Common Gurnakd {Trigla). 



