THE AQUARIUM, APRIL, 1893. 



35 



according to the species of the fish and 

 the modifying influences of the climatic 

 surroundings and peculiarities of the 

 locality the fish may inhabit. Also, 

 when the spawning or breeding ap- 

 proaches, the males of many species 

 assume a most gorgeous array, in obe- 

 dience to a general law of nature, uni- 

 versal throughout animal life to a 

 greater or lesser extent. When the 

 spawning has been completed the un- 

 usual brilliancy of colors disappears, the 

 fish again resuming the ordinary color 

 of his species. 



The next thing most noticeable are 



placed where the hind legs of animals 

 and the legs of birds and man are 

 found. The dorsal fin is that one 

 found upon the back of the fish, and 

 does not necessarily exist in pairs, 

 though some species are supplied with 

 two, while others again may possess 

 more. In case of plurality, that fin 

 located nearest the head is denominated 

 the first dorsal fin, the next one the 

 second, and so on. That fin situated 

 behind the anus receives its name from 

 that part, and in consequence is known 

 as the anal fin. The tail of the fish is 

 properly called the caudal fin, though. 



expanded projections from the body, 

 and which are more or less in constant 

 motion, propelling the fish here and 

 there and guiding it in the direction it 

 wishes to go. These are the fins, and 

 are named according to their location 

 upon the body of the fish, and subserve 

 various purposes. As previously stated, 

 the fins, or at least a part of them, cor- 

 respond with the limbs of warm-blooded 

 animals, and are also arranged in pairs, 

 one on each side of the body. The 

 pectoral fins are those situated in the 

 place corresponding with the forelegs 

 of animals, the wings of birds, or the 

 arms of man — the ventral fins being 



there seems to be a popular impression 

 that the term ''caudal fin" implies the 

 existence of a fin situated in the neigh- 

 borhood of the tail, but which is not 

 the case. 



The shape of the caudal fin differs 

 greatly and is often a denominative 

 characteristic. It is emarginate, when 

 it is slightly forked ; furcate, when 

 forked like the tail of a common gold- 

 fish ; forficate when deeply forked like 

 a swallow tail ; the tail is called 7-ound 

 when it shows the shape of an open fan ; 

 and truncate, when it appears to be 

 straight cut-off ; double-truncate it is 

 called, when it looks cut-off slanting on 



