39 o THE POPULAR SCIENCE MONTHLY. 



had been swallowed, it proved ... to have a diameter several times 

 exceeding that of its enemy, whose stomach it had distended to an 

 unnatural and painful degree." The action performed by the fish in 

 these cases is not, however, a real swallowing, but more like the similar 

 process executed by serpents. 



The interest of Dr. Giinther's book does not end with the account 

 of deep-sea fishes, but the chapters devoted to that subject and to classi- 

 fication illustrate the most striking discoveries that have been recently 

 made in ichthyology. Among the curiosities of fish-life that please 

 and amuse as well as instruct, is the story of the fighting-fish of Siam, 

 which, on seeing another of its species, or even its own image, in a mir- 

 ror, becomes suddenly excited, and of which, though it is dull in hue at 

 other times, " the raised fins and the whole body shine with metallic 

 colors of dazzling beauty, while the projected gill-membrane, waving 

 like a black frill round the throat, adds something of grotesqueness to 

 the general appearance." The Siamese are infatuated with the com- 

 bats of these fishes, staking on the results considerable sums, and some- 

 times their persons and families, while the license to exhibit fish-fights 

 is farmed, and brings in no small revenue to the royal treasury. 



The peculiarity of the flounders, and other flat fishes, by which the 

 eyes, normally situated in the young, move around as the animal grows, 

 until they are both on the same side of the body, is well known, but 

 the manner in which the transposition is effected is still in question. 

 There is, moreover, no end to the wonders to be found in fishes' eyes. 

 Those of the genus Anableps, known in Demerara as " four eyes," 

 have the iris horizontally divided by a black band, which almost justi- 

 fies their name; and as these fishes frequently swim with the head half 

 out of the water, it is presumed that the upper and lower portions of 

 the cornea are adapted for the different density of the media in which 

 they are respectively used. The " star-gazers " ( Uranoscopus) , and 

 others, have eyes that can be raised or lowered at will; but the most 

 remarkable instance of mobility in these organs seems to exist in cer- 

 tain gobies of the genus Periophthalmus and its ally JBoleophthalmus, 

 which might be called " oglers," as they have the power of thrusting 

 their eyeballs far out of the socket, and turning them as freely as a 

 chameleon rolls his. These fishes are also remarkable for another 

 faculty, toward which their versatile eyes must contribute not a little. 

 At low water they remain on the muddy flats, and hunt for their prey, 

 which consists of small crustaceans and other marine animals, mak- 

 ing rapid leaps by the aid of their fins and tails, which are strong; 

 and when their eyes are retracted they are protected by a membra- 

 nous lid. 



Then the fishes that travel over land, the flying-fishes, with the 

 controversy as to whether they really fly or only seem to (with Dr. 

 Gunther denying the reality of the flight, and others affirming it from 

 their personal observations), and the fish that build nests, like the 



