120 NATURAL HISTORY. 



reddish. The dorsal fin is elevated with more rays than in the species of Coregowis, the fibh is of a 

 violet colour, with purple spots, and ths trunk is marked with a few small round black dots. 



The Argentina hebridica is a member of another genus, which, while entering fresh waters, 

 is also found in the European seas at great depths. It somewhat resembles a Smelt in form, size, and 

 odour, but is covered with rather large scales. Species of this genus have been dredged from a depth 

 of over 2,000 fathoms in Arctic and Antarctic waters. 



FAMILY VIII. PERCOPSID^E. 



The Percopsidie, represented by Percopsis guttatus, are characterised by having the body covered 

 with ctenoid scales. The species is found in Lake Superior. 



FAMILY IX GALAXLTLE. 



The Galaxidss include two genera of fresh- water fishes, which all have the bcdy naked, and have 

 hook-like teeth on the tongue, and conical teeth in the jaws and on the palatine bone. The species 

 occur in Aiistralia, New Zealand, and the southern part of South America. They vary from two 

 inches to about seven or eight inches in length. The genus Galaxias has only been found burrowing 

 in clay, at some distance from water. 



FAMILY X. MORMYRID^E. 



This family comprises three genera of fishes from tropical Africa, The pre-maxillary bones imite 

 into a single bone ; the inter-operculum is sometimes rudimentary. All the fins are well developed, 

 but there is no adipose fin. A series of pores extends along the base of the dorsal and anal fins. The 

 genera are distinguished by the presence or absence of teeth on the tongue, and the species are defined 

 by the form of the dorsal fin, length of the snout, and the size of the scales. Most of the species of 

 Mormyrus are found in the Nile, where the other genera. Mormyrops and Hyperopisus, also occur. 



FAMILY XL GYMNARCHID.E. 



The Gyrnnarchidse are known only from the Gymnarchus niloticus, found in the Nile and rivers 

 of West Africa. It reaches a length of six feet, has an eel-like body, and is chiefly remarkable for the 

 cellular character of the air-bladder, which is capable of being distended. As in the preceding family, 

 the upper jaw is formed of both the maxillary and pre-maxillary bones, and there is similarly a cavity 

 extending into the interior of the skull on each side of the parietal bone, but covered with a thin 

 bony plate. Another point of resemblance is a series of pores along the base of the dorsal fin. In 

 this fish, however, the anal and ventral fins are absent. The tail tapers, and has no caudal fin. It 

 i-esembles Mormyrus in having an imperfectly developed electric organ on the tail, with the usual 

 prismatic structure, but without electric functions. 



FAMILY XII. ESOCLD^E. 



This family comprises the Pikes, which all belong to the genus Esox, and occur in the fresh 

 waters of the temperate parts of the northern hemisphere. Several species of this genus are limited to 

 North America ; but the Eiiropean Pike (Esox lucitis) also occurs in the northern parts of North 



America, as well as in Northern Asia. 



THE PIKE.* 



The Pike (see figure on p. 1), when full grown, may reach a length of five or six feet. In Loch 

 Lomond, examples have occasionally been taken weighing about eighty pounds ; one is recorded from 

 the Shannon that weighed ninety-two pounds. The fish is certainly long-lived, and Gesner refers to 

 an example, said to have b3en nineteen feet long, which weighed 350 pounds. In the Middle Age;; 

 rings were sometimes put in the gill-covers of fishes ; and on evidence of this kind it has been 

 supposed that Pike have sometimes lived for more than 250 years. The young are said in the first 

 year to grow to a length of eight or ten inches ; in the second year they increase to twelve or 

 fourteen inches ; and in the third year the length is eighteen or twenty inches ; after which the 

 weight and size augment in proportion to the supply of food, for ,the Pike digests rapidly, and 

 therefore, stimulated by hunger, is bold and active in the pursuit of prey. The stories of its voracity 

 are almost inexhaustible. In one case a Pike swallowed the head of a swan ; in another case this fish 

 seized on the lips of a mule that had gone down to the Rhone to drink. It is said sometimes to fight 

 with the otter for possession of fish. The instances are many of Pike seizing the hands and feet of 

 bathers. An early writer, Dr. Crull, quoted by Couch, states that a Pike had been captured 



* Esox lad us. 



