GENERAL PACTS ABOUT SEA FISH 3 



water. It may be questioned, however, whether any true fish 

 ever brought to life will be found to lack, true fins. They may 

 be small, or even atrophied ; but in some form or other, allowing 

 for all possible variation in size and number, they will be found 

 to persist. 



The fishes of the world are divided into a number of sub- 

 classes, the arrangement differing slightly according to various 

 authorities. One of these contains the aforementioned lung- 

 fishes, and to another is relegated a curious form, the " bichir " 

 of the Nile. These, being without representatives in our seas, 

 need not further occupy our attention. If from the rest we 

 eliminate the Arctic chimasra and sturgeon, both of which forms 

 are briefly described in Chapter XIV., we have to concern 

 ourselves in these pages with only two great groups — the 

 comparatively useless cartilaginous fishes (Selachii), which 

 include the sharks and rays, and the variously valuable bony 

 fishes (Teieostomi), which include, with the exception of a few 

 rays, all the fishes which commonly find their way to our 

 tables. Before proceeding further to examine briefly some of 

 the leading characters and habits of our sea fish generally, it 

 may be as well to distinguish unmistakably between these two 

 great groups. For this purpose, let us distinguish between a 

 typical representative of either, the bass (^Labrax) standing for 

 the bony fishes, the tope (Galeus) for the sharks. 



The bass has a bony frame, and its body is covered with 

 silvery scales that are easily detached from the tough skin. 

 The tope has a skeleton of gristle, or cartilage, and its skin has 

 no silvery scales, but is granulated, like sand-paper, with a 

 tooth-like covering. The gills of the bass, four in number 

 on either side, open into one cavity protected by bony gill- 

 covers. Those of the tope, which number five on either side, 

 and are supplemented by holes called " spiracles," open 

 separately on the side, showing five distinct gill-slits unpro- 

 tected by any covers. The tope is able to close its eyes by 



