THE BLIND-FISH. 275 



The skeleton of the Leptocephalidse, or Glass Eels as they are termed, from their Eel-like 

 shape and singular translucency, is very imperfect, merely consisting of cartilage, and so 

 slight that even in the head, where the greatest strength is required, the brain can be seen 

 through the translucent skull in which it lies. Their bodies are always extremely compressed 

 and mostly leaf-like, so transparent that when lying in a vessel containing water they would 

 hardly be noticed, and the lateral line is formed by The intersection of the muscles. 



The Pig-nosed Glass Eel may be known by the lengthened form of its head and snout, 

 which are far longer in proportion to the dimensions of the fish than in any other member of 

 the family. The generic term Hyoprorns literally signifies swine-beaked, and in former days 

 was applied to a certain kind of galley which had a long and slightly turned-up beak. The 

 sudden height of the body just behind the head is very remarkable, and on close examination, 

 a row of mucous pores will be found along the jaws and on the head. The eyes are not very 

 large, and the general length of the species is between four and live inches. As its specific 

 name imports, it has been taken at Messina. 



The Hair-tailed Glass Eel is much longer in proportion than the last-mentioned 

 species, and its body is so extremely compressed that it is hardly thicker than the paper 

 on which this account is printed. This species is also found at Messina. The jaws are skori 

 and round, the eye rather small, and the tail tapers away to a hair-like point. The length 

 of this fish is rather more than a foot, and a row of minute points runs along each edge of the 

 body. 



The typical genus Leptocephalus is a rather large one, containing more species than the 

 four preceding genera together. 



The Round-headed Glass Eel derives its specific name of Tagnia, or tape-worm, on 

 account of its resemblance to that unpleasant internal parasite. Its head is, as its name 

 denotes, short and much rounded, and the eyes are globular, projecting, and extremely 

 large. The jaws are tolerably well furnished with small teeth. In shape it is long and 

 rather rounded, and the absence of fins renders its resemblance to a tape-worm extremely 

 striking. It seems to be an Asiatic species, having been captured in India and the neighboring 

 islands. 



In the Anglesey Morris (Leptocephalus morrisi), another example of this genus, the 

 head is blunt, the eye moderate, the body much compressed, and deepest at the latter third of 

 its length. When living, its polished surface reflects gleams of iridescent light as it winds its 

 graceful way through the sea weeds among which it loves to sojourn, like a ribbon of animated 

 nacre. But when dead and placed in spirits, all the delicate opalescence of its body fades, and 

 soon deteriorates into an opaque dull whiteness like wet parchment. 



THE BLIND-FISH. 



The reader will remember that on several occasions it has been deemed expedient to give 

 examples of remarkable deviations from the ordinary system, and to call attention to the 

 wonderful economy of nature, which is most averse to wastefulness, and declines to expend its 

 powers on organs that if existing would lie in abeyance. A recent example of such modifica- 

 tion has been given in the proteus, on page 186, that curious reptile, or semi-reptile, which 

 inhabits caves wherein penetrates no ray of light, and which, having no need of external eyes, 

 is altogether devoid of such useless organs. 



The Blind-fish of America affords another instance of similar economy in structure. 

 Living, like the proteus, in a subterranean and perfectly dark grotto, it needs no eyes, and 

 in consequence possesses none, their place being merely indicated by two minute black clots 

 on the sides of the head. The head is naked, but the body is covered with scales and the jaws 

 are furnished with some small but sharp teeth. Its color is whitish-gray, as is, indeed, mostly 

 the case with animals that have been long deprived of the color-giving sunlight. The grotto 

 which contains this very remarkable little fish is in Kentucky. 



Of the Blind-fishes, family Amblyopsidce, living in caves, three genera are now known. 



