CLASS PISCES. 535 



noti, but their back is furnished all along with a soft, 

 rayed fin, and there are none behind the anus, or 

 under the tail, which is terminated in a point. Their 

 head is conical, and naked ; their mouth is small, 

 furnished with small trenchant teeth, on a single 

 range. 



But one is known, from the Nile, Gymnarchus Nilo- 

 ticus, Cuv., discovered by Mr. Riffault. 



Leptocephalus, Pennant, 



Have the cleft of the gills open in front of the pec- 

 torals, and the body compressed like a ribbon. Their 

 head is extremely small, with a short, and rather 

 pointed muzzle, the pectorals almost imperceptible, 

 or actually wanting ; the dorsal and anal in like man- 

 ner scarcely visible, united together at the point of 

 the tail ; the intestines occupy only an extremely 

 narrow line along the inferior edge. 



One species is known which frequents our coasts 

 and those of England, Leptocephalus morissii, Gm., 

 Lacep. II. iii. 2 ; but there are several others in the 

 seas of warm climates ; they are all as thin as paper, 

 and as transparent as glass, so that the skeleton is not 

 even perceptible. A more profound study of their 

 organization would be one of the most interesting to 

 which travelling naturalists could devote themselves. 



Ophidium, L. Donzelles, {French), 



Have, like the true eels, the anus pretty far back, a dor- 

 sal and an anal fin, which unite with that of the tail to 



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