OPHIDIID^. 549 



Of the remaining genera belonging to this group, Brotu- 

 lophis, ITalidesmus, Dincmatichthys, and Bythitcs are surface 

 forms ; Siremho and Fteridium inhabit moderate depths ; 

 Rhi7wnus is a deep-sea fish. 



II. Ventral fins replaced hy a pair of hifid filaments 

 (barlels) inserted heloiu the glosso-hyal : Ophidiina. 



Ophidium. — Body elongate, compressed, covered with very 

 small scales. Eye of moderate size. All the teeth small. 



Small fishes from the Atlantic and Pacific. Seven species 

 are known, differing from one another in the structure of the 

 air-bladder (see p. 145). 



Genypterus is a larger form of Ophidium, in which the 

 outer series of teeth in the jaws and the single palatine series 

 contains strong teeth. 



Three species from the Cape of Good Hope, South 

 Australia, New Zealand, and Cliili are known. They grow to 

 a length of five feet, and have an excellent flesh, like cod, 

 well adapted for curing. At the Cape they are known by the 

 name of " Klipvisch," and in New Zealand as " Ling " or 

 " Cloudy Bay Cod." 



III. No ventral fins whatever ; vent at the throat: FiERAS- 

 FERINA. 



These fishes {Ficrasfcr and Enchcliophis) are of very small 

 size and eel-like in shape ; the ten species known are found 

 in the Mediterranean, Atlantic, and Indo-Pacific. As far as 

 is known they live parasitically in cavities of other marine 

 animals, accompany Medusce, and more especially penetrate 

 into the respiratory cavities of Star-fishes and Holothurians. 

 Not rarely they attempt other animals less suited for their 

 habits, as, for instance, Bivalves ; and cases are known in 

 which they have been found imprisoned below the mantle of 

 the MoUusk, or covered over with a layer of the pearly sub- 

 stance secreted by it. They are perfectly harmless to their 



