BONY FISHES AND GANOIDS. 497 



African and Asiatic genus Clarias being an example of this section. To the 



second section belongs the typical Saiinis, of which tliere are five species, from 



the temperate regions of Asia and Eastern Europe. Here the rayed portion 



of the dorsal fin is much reduced in length, 



and, if present at all, confined to the 



hinder region of the back, while the fatty 



dorsal is also small or wanting. On the 



other hand, the anal is long, occupying 



nearly the whole of the caudal region. 



The third group is small, and of little 



importance ; but the fourth is a very 



large one, and includes the Nilotic 



Bagrus (represented by the bagad), the Mg. 26.— The 'Wei.s. 



South American Pimelodiis, the widely 



spread Ariv,s, the gigantic Asiatic Bagariui, and a host of others. In 



this group the short-rayed dorsal does not include more than a dozen rays, 



and is placed far back on the body ; the fatty dorsal is present, although 



often small ; and the anal is much shorter than the caudal portion of the 



backbone. If barbels are present on the nose, they belong to the hinder 



of the two pairs of nostrils. Passing over the fifth group, and likewise 



omitting mention of the seventh and eighth, attention may be directed to the 



sixth, on account of its including a number of South and Central American 



forms in which the body is invested in a more or less complete armour, 



formed of large plates of bone. As examples, may be mentioned the short 



and deep-bodied Callichthxjs, and the long and slender Loricaria and Hypo- 



ptopoma, all three of which are abundantly represented in the Amazons. 



Section C. — Plectispondyli. 



The third section of the Physostomi is an important one, as containing the 

 large family of the carps, together with two other family groups. In both 

 the Nematognathi and Plectispondyli the first four vertebrae in the neck are 

 specially modified and united into a single mass ; but the subopercular bone, 

 which, as already mentioned, is wanting in the gill-cover of the former sec- 

 tion, is present in that of the latter. 



Although the numerous members of the large fresh-water family of the 

 carps come under the designation of " coarse-fish," yet, owing to its cheap- 

 ness, their flesh ailords an important article of food among 

 certain races and classes, while many of the species afford Family 



sport to those anglers who do not aspire to the highest grade Cyprinidce. 

 of their pastime. All the carps liave naked heads and tooth- 

 less sucking mouths ; such teeth as they may possess being confined to the 

 pharyngeal bones of the throat. Usually the body is covered with scales, 

 but if these are wanting the skin is naked. Some kinds are provided with 

 false gills of a glandular type ; and the air-bladder, when present, is large, 

 and may be divided either longitudinally or transversely into two portions. 

 When longitudinally divided, it has a bony capsule. In no carps is there a 

 fatty dorsal fin ; but the mouth often bears short barbels. Carp are un- 

 known both in Central and South America and Australasia, but are elsewhere 

 almost universally distributed. Their distribution is thus coextensive with 

 the Arctogseic realm, as defined in the introductory part of the section on 

 33 



