l 22V) fishes. 



nidation, the use of which cannot be divined*. The head is oblong, 

 compressed, naked, and the skin prevents both the opereula and the rays 

 from being seen externally; rest of the body scaly; teeth small and 

 crowded, and on the middle of each jaw scarcely perceptible. The Ster- 

 narchi, like the preceding fishes, inhabit the waters of South America j. 



Gymnarcuus, Cuv., 



Have the body scaly and elongated, and the gills slightly open before the 

 pectorals, as in Ciymnotus ; but a fin, with soft rays, occupies the whole 

 length of tbe back; and there is none behind the anus, nor under the tail, 

 which terminates in a point. Tbe head is conical and naked, the moutb 

 imall, and furnished with a single row of small trenchant teeth. 



Q. niloticua, Cuv. The only species known; discovered in the 

 Nile by M. Riffault. 



LePTOCEPHALUS, Pennant. 



The members of this germs have the branchial aperture before the pec- 

 torals ; body compressod like a ribband ; head extremely small, with a 

 short and slightly pointed snout; pectorals almost imperceptible, or totally 

 wanting; the dorsal and anal hardly visible, and uniting at the point of 

 the tail. The intestines occupy but an extremely narrow line along the 

 inferior edge. One species only is known, 



L. morieii, Gm. ; Lacep, IT, iii, 2, which inhabits tbe coasts of 

 France and England. Several other species, however, are found in 

 the seas of hot climates, all of them as thin as paper, and transpa- 

 rent as glass, so that even the skeleton is not visible. The deeper 

 study of their organization is one of the most interesting to which 

 travellers can devote themselves. 



OPHIDIUM, Lin. 



The Donzelles have the anus, as the Eels, properly so called, far 

 behind; a dorsal and an anal fin united with that of the tail, and termi- 

 nating the body in a point; this body is besides elongated and compressed, 

 which has led to its being compared to a sword; if. is invested, like that 

 of an Eel, with small scales planted in the thickness of the skin. The 

 Donzelles, however, dillei from Eels in their well-cleft branchiie, which 

 are furnished with a very apparent operculum and a membrane with short 

 rays. Their dorsal rays are articulated, but not branched. 



Oi'inmi M, CuV. 

 The Donzelles, properly so called, have two pairs of small cirri under 



the throat, adhering to the point of the hyoid hone. There are two of 



them found in the Mediterranean. 



* I think, a*, far as mv observation goes, that the separation is accidental, and 



Unit it really in one of llie muscles of the tail, which is easily detached in conse- 

 quence of the skin being more fragile in this particular place. 



f Qy mnotus albifront, Pall. Spic, Zool, VIII, pi, vi, t'. I; Lacep. N,vi, HG, ;5. 



N. it. The Gymnotm urns, <>< fleraqfer, belongs t<> the genua Ophidium, aval t lie 

 Gymtiotus notoplerut, Pall, and Gm., Notopt&re capirat, Lacep., to the Herrings. 



