SI MARU BACE.E. 



691 



every prick that it gives, though very minute, festers, 

 and threatens gangrene. This is P. ikapar. It is 

 deep black on the back, and white on the belly, with 

 four yellow stripes extending from the muzzle to the 

 tail. 



Callicthys. These have the body completely co- 

 vered on the sides by four rows of bony plates ; but 

 the muzzle and the under part are naked. The first 

 dorsal has the spine short and weak, and the second 

 dorsal has only one ray; but the spines in the pecto- 

 rals are strong and rough. The opening of the mouth 

 is narrow, and the teeth are very minute. The fishes 

 sometimes crawl and climb out of the water in the 

 same manner as eels. 



The subgenera, of which we have now given a list, 

 are those that make up Cuvier's genus Silurns ; and, 

 notwithstanding the extent to which it is subdivided, 

 the subdivisions do not reach all the particulars of the 

 characters of the species. Our information respecting 

 them and the other genera that make up the family is, 

 however, very imperfect, though the fishes are very 

 numerous. 



MAL^EPTERURUS. This genus gets its name from 

 the only fin on the back being soft. There is no dorsal 

 fin properly so called, but only a little adipose append- 

 age near the tail. There is not a vestige of spine in 

 the pectorals ; nor any kind of armature upon any 

 part of the body. The teeth are small, and cover a 

 large crescent on the surface of the mouth. 



There is only one known species of the genus, M. 

 electricus (the Silurus elcctricus of Linnaeus). It in- 

 habits the rivers of the warmer parts of Africa, where 

 it attains the length of from a foot to a foot and a 

 half. It is a very slimy fish, and has the skin marked 

 with very many black spots upon a white ground. The 

 most remarkable character about it is an electric 

 power, similar to that of the Gymnotus and the Tor- 

 pedo; but, from the smaller size of the fish, not so 

 formidable as it is in these. 



The Arabs, who capture it in great numbers in the 

 Nile, call it Raad, or the "thunderer ;" but so far are 

 they from having any superstitious dread of it, that 

 they readily eat its flesh, and apply its fat for medi- 

 cinal purposes, chiefly fumigations by burning it. The 

 electric apparatus appears to be the same in this as in 

 all the other electric fishes, namely, a series of tubes 

 divided into numerous cells by cross partitions, and 

 filled with a fluid. This is so perfectly analogous to 

 a common galvanic apparatus, that there seems every 

 reason to believe that, in the one as in the other, the 

 energy is obtained by a decomposition ; but whether 

 the decomposition of water we are unable to say. 

 As is the case in the others, the electric apparatus is 

 very amply furnished with nerves. 



ASFREDO. The characters of this genus are very 

 well delined. Their head is very short, and the fore 

 part of the body very broad, owing to the large size 

 of the shoulder-bones ; the tail is also very long ; the 

 eyes are small, and have an upward aspect. Their 

 most remarkable character, however, and one which 

 distinguishes them from all the other bony fishes, is 

 the immobility of the gill-lid. The opening of the 

 gills by which the water is discharged is a simple slit, 

 at the back part of the side of the head. The species 

 are not numerous. 



LORICARIA. This genus are named from the bony 

 plates that cover the whole body and head ; and they 

 are distinguished from all the other armed Silnridce, 

 by the mouth opening under the muzzle, Among 



the other members of the family, Synodontis is the 

 one which has the mouth most nearly resembling that 

 of this one, but there are many differences. The in- 

 termaxillary bones are small, and suspended under 

 the muzzle; and the mandibularies are transverse, not 

 united, and furnished with long and slender teeth, 

 crooked at the points. A large circular veil of mem- 

 brane surrounds the mouth ; and the bones of the 

 pharynx are covered with teeth like a pavement. The 

 gill-lids properly so called are as immoveable as they 

 are in the genus Aspredo; but there is a small move- 

 able plate jointed to the side of each, which appears 

 to perform the function of the whole. They have four 

 rays in the gill-membrane. The first rays of the dor- 

 sal, of the pectorals, and even of the ventrals, are 

 furnished with strong spines. They have no caecal 

 appendages to the intestines ; and it does not appear 

 that they have any air-bladder, though every other 

 genus in the family is provided with one. In conse- 

 quence of considerable differences in the characters 

 of the known species of the genus, it has been divided 

 into two subgenera. 



Loricaria properly so called. The fishes of this 

 subgenus have only one dorsal fin, situated far for- 

 ward on the body ; the membranous veil or append- 

 age to the lips is furnished with barbules, and in 

 some cases it is roughened all over with papillae ; and 

 the under part of the body is covered with osseous 

 plates, as well as the upper and lateral parts. 



One of the most characteristic species of this sub- 

 genus is L. cataphracta of Linnaeus. It is an inhabit- 

 ant of the fresh waters of South America. It has the 

 caudal fin much forked, and the first ray of the upper 

 lobe very long, often longer than the whole body of 

 the fish ; but this is apt to be broken in dried speci- 

 mens, and thus the drawings taken from them give a 

 very imperfect idea of the true character of the fish. 



Hypostomus. These get the name of "under mouth" 

 to distinguish them from the preceding subgenus. They 

 have a second dorsal fin of small size, and with only 

 a single ray. Their labial membrane is beset with 

 papillae ; but it has no barbules, except a small one 

 at each side of the upper jaw. The belly is also 

 without osseous plates. Their intestinal canal is 

 much convoluted, and at least five times the length 

 of the body. Like the preceding subgenus, they are 

 known only as inhabitants of the fresh waters of 

 South America. 



Such is a very brief outline of the family of the 

 SiluridcB, which are, next after the salmon family, per- 

 haps the most interesting of the fresh water fishes ; 

 and they far exceed them in size. They are among 

 fishes what the hippopotami are among the river 

 mammalia ; and both races are most abundant in the 

 same latitudes, and also in the very same rivers. 

 They, however, lie too far from the scene of accurate 

 observation for our being able to say much of their 

 relations to the rest of nature, or the part which they 

 more immediately perform in the system ; but they 

 are so numerous, so varied, and some of them of such 

 size, that their function must be important. 



SIMARUBACE^E. A small natural order con- 

 taining three genera and five species. The genera 

 are, Simaruba, Semaba, and Quassia. They are trees 

 or shrubs with an excessively bitter bark, a milky 

 juice, and pinnated leaves. The Simaruba officinalis 

 is well known as the most pure and intense bitter 

 hitherto discovered. The same quality exists, in a 

 milder degree, in the rest of the order. The flowers 

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