SILl-RIDi 



SILURID.E. 



77 



Dud yellowi-h on the belly, and the whole body U covered with dark 

 ipoU; ix barbules lurrouod the mouth, and two of these, which 

 have their origin (one ou each aide) just above the angle of the mouth, 

 are very long. 



Mr. Y anvil observes, " The Silurui U represented at sluggish in its 

 habiU, and a alow iwimmer, taking iu prey by lying in wait for it, in 

 a manner somewhat similar to the Augler, Lopkiut : hiding itself 

 in hol or soft mud, and apparently depending upon the accidental 

 approach of fishes or other animal*, of which lU long and numerous 

 barbules may be at the same time the source of attraction to the 

 victims, and the means of warning to the devourer. From its formid- 

 able siie, it can have but few enemies in the fresh water ; and from 

 them, it* dark colour, in addition to its habit of secreting itself either 

 in holes or soft mud, would be a sufficient security. In spring, the 

 male and female may be seen together, about the middle of the day, 

 near the banks or edges of the water, but soon return to their usual 

 retreats. The ova, when deposited, are green ; and the young are 

 excluded between the sixteenth and nineteenth days. 



" The flesh of the Silurui U white, fat, and agreeable to many 

 persons as food, particularly the part of the fish near the tail ; but on 

 account of its being luscious, soft, and difficult to digest, it is not 

 recommended to those who have weak stomachs. In the northern 

 countries of Europe the flesh i* preserved by drying, and the fat is 

 used as lard." 



In the ' Histoire Naturelle des Poissons,' it U stated that the present 

 fish is so voracious, that it has been known, in several instances, to 

 devour children ; and in one instance the body of a woman was found 

 in one of these fishes. 



Several examples of the restricted genus Silariu are found in Asia. 



Cuvier separates from the typical .S'i/uri, as a genus, the .SiVttriu 

 myittu of Linnicus, and some others, on account of the compressed 

 form of the body, and the dorsal fin having a strong bony spine in 

 front, which U denticulated on the hinder margin. The body is 

 deepest near the middle, but tapers somewhat suddenly towards the 

 extremities. The head is small and depressed, and the eyes are placed 

 low down. 



The species upon which Cuvier founds this genus to which he 

 applies the name of Sdtilbe are found in the Nile, but there are 

 others described in this author's great work on fishes, one of which is 

 found in the Senegal and another in India. 



Cetoptii. This genus is founded by Agassiz on certain species found 

 in Brazil, wliich in their affinities approach the genus Siluriu, but are 

 distinguished by the extremely small size of their eyes. 



Baijnu, Cuvier. The species of this genus are distinguished from 

 those of the genus Silurut, as restricted, by their possessing an adipose 

 fin on the hinder part of the back. The body is naked that is, 

 unprovided with bony plates and the mouth is provided with bar- 

 bules, the number of which, varying iu different species, has been 

 selected for the minor divisions of the group. Numerous species are 

 found in the Indian and African rivers. 



Pimdodiu, Lacop. Differs from flayrui in having no teeth on the 

 vomer ; the palatines however are often provided with teeth. The 

 species are very numerous, and are found both in the Old and New 



Phraetocepkaliu, Agawiz. This genus contains but one species, an 

 Inhabitant of the Brazils ; its generic distinction consists in its pos- 

 sessing some incomplete osseous rays enchased in the upper margin of 

 the adipose fin. 



PtnlyHoma, Agassiz. It is composed of several South American 

 species which have the muzzle depressed, and are remarkable for the 

 great number of their branchiostegous rays, which amount in some to 

 fifteen in number. 



Galtichtkyt, Cur. and Val. This genus U nearly allied to Bagria, 

 but diKtinguished by the head being round and unprotected by any 

 distinct bony plate ; the branchiostegous rays are 6 in number. One 

 species is found at the Cape of Good Hope, a second U said to be 

 found both in North America and at Rio Janeiro'; several species occur 

 in Itrazil, and the Ganges also furnishes a species of the present genus. 



Silundia, Cuv. and Val. This genus is founded upon a fish from 

 the Ganges, which has the head small and smooth, a very small 

 adipose fin, and a long anal fin. 



Arita, Cuv. and Val. Contains many species allied to the Bagri, 

 bat dintingnished by their palatine teeth forming two distinct and 

 widely-separated masses. They are found in the tropical portions of 

 both continents, and also in North America. 



Aueheniplrnu, Cuv. and Val. Distinguished by the small sice of 

 the bead, the very minute size of the teeth, and there being 6 

 hraochiostegons rays. All the known species are from the tropical 

 |iortions of South America. 



TraeMyoplenu. Founded by Messrs. Cuvier and Valenciennes, 

 ii[>n n minll Silurian from Cayenne, in which there is no adipose fin. 

 Tbii t?eth are fine, like the pile of velvet, and the palate U destitute of 

 te<-th ; the barbules sre 6 in number. 



]lyiij,li'linlmHi (Spix), Cuv. and Val., is composed of but few 

 specie*, and these am from the tropirnl portion* of South America. 



Ayeneiona (Laoc'pode), Cuv. and Val Characters the same as in 

 /' '/m, excepting that there are no barbules, properly so called. 



All the specie* are from South America. 



Synoilonin, Cuv., is composed of specie) found in the Nile and 

 Senegal, which have an adipose fin; the muzzle narrow, and terminated 

 by an ethmoid, which supports two small intermaxillary bones armed 

 with bristle-like teeth; the lower jaw composed of two short and 

 slender rami, bearing in front a mass of teeth, which are in the form of 

 very slender lamina and closely packed. Each of these teeth U 

 attached to the jaw by a flexible and very slender stalk. 



Dorat, Laclpcde. The species of this genus are distinguished by 

 the lateral line being armed with bony plates, which are carinated and 

 terminate in a spine. They are the most powerfully armed of all the 

 Stlurida ; thus the Spanish colonists in South America have given to 

 them the name of Mata-Caiman (or Crocodile-Killer), because it often 

 happens that when they are swallowed by these large reptiles, the 

 OMophagus and pharynx of those animals are so lacerated by the spine* 

 of the Siluriu as to cause death. Strabo also (p. 824, Cauub.) attri- 

 butes similar powers to certain fishes of the Nile, which he called 

 Xotpos, and which are supposed by some naturalists to belong to the 

 modern genus Synodonti*. 



Dorat is divided into two sections on account of the structure of 

 the mouth. In some it is situated at the end of a depressed muzzle, 

 and ia provided with two broad bands of delicate teeth, both in the 

 upper and lower jaws. In others the opening of the mouth is 

 situated on the under side of a conical muzzle, and the opening is of 

 a circular form here the teeth are either wanting or are hardly 

 visible ; the maxillary barbules are sometimes furnished with small 

 lateral branches. To the first of these sections belongs the Siluriu 

 cot tat ua of Linnaeus, a species found in the rivers of Guiana. 



A species of Doras, described by Dr. Hancock, in the fourth volume 

 of the ' Zoological Journal,' p. 241, under the name of 1). costattu, is 

 a native of Demerara, where it is called the Flat-Head Hassar. It 

 possesses the singular property of deserting the water and travelling 

 over land. Dr. Hancock describes a second species, called the Round- 

 Headed Hassar. 



Both the species make nests, in which they lay their eggs in a 

 flattened cluster, and cover them over most carefully. Their care does 

 not end here. They remain by the side of the nest till the spawn U 

 hatched, with as much solicitude as a hen guards her eggs ; both the 

 male and female hassar, for they are monogamous, steadily watching 

 the spawn, and courageously attacking any assailant. Hence the 

 negroes frequently take them by putting their hands into the water 

 close to the nest, on agitating which the male hassar springs furiously 

 at them, and is thus captured. 



" The Round-Head forms its nest of grass ; the Flat-Head of leave*. 

 Both at certain seasons burrow in the bank ; they lay their eggs only 

 iu wet weather. I have been surprised to observe the sudden appear- 

 ance of numerous nests iu a morning after rain occurs, the spot being 

 indicated by a bunch of froth, which appears ou the surface of the 

 water over the nest ; below this are the eggs, placed on a bunch of 

 fallen leaves or grass, if it be the littoral species, which they cut and 

 collect together. By what means this is effected seems rather mys- 

 terious, as the species are destitute of cutting teeth. It may possibly 

 bj by the use of their serrated arms, which form the first ray of the 

 pectoral fins." 



Callichlhyt, Linn., belongs to this family. [CAI.LICHTHTS,] 



Aiya, Cuv. and Val. The principal characters of this genus are- 

 teeth bifid at the extremity, and with the points curved inwards ; 

 palate destitute of teeth ; opening of the mouth large ; maxillary 

 barbules two in number ; anterior dorsal fin small, and with the front 

 ray feeble ; adipose fin long ; the other fins with the outer rays 

 prolonged into a filament. 



The species which forms the type of this genus (A. tabalo, Cuv. and 

 Val.) is a small fish about 8 inches in length, which was brought by 

 Mr. Pentland from Upper Peru, being found in the neighbourhood of the 

 mission of Santa Anna, at a height of from 4500 to 4300 French metres 

 above the level of the sea. The specimen was given to M. Valenciennes, 

 who prized it much, since it threw a light on the affinities of a fish 

 described by Humboldt under the name 1'imeloJut Cyclopun, relating 

 to which that author has given such an interesting account. The 

 Pimdodiu Cyclopum, wliich M. Valenciennes thinks most probably 

 belongs to the present genus, is about 4 inches in length, and is found 

 in lakes at the height of 3500 metres above the level of the sea. But 

 the most remarkable circumstance relating to these fishes U that they 

 are frequently ejected in the eruptions from the volcanoes of the 

 kingdom of Quito, and in such quantities that the fetid odour arising 

 from their putrefaction was perceived at a great distance, and the 

 putrid fevers which prevailed in those districts were attributed to the 

 miasmata they produce. These fishes sometimes issued from the 

 crater of the volcano, and sometimes from lateral clefts, but constantly 

 at an elevation of from 6000 to 5200 metres above the level of the 

 sea. In a few hours millions are seen to descend from Cotopaxi, with 

 great masses of cold and fresh water. 



Brontct, Cuv. and Val., is founded upon a fish possessing all the 

 characters of the preceding gemix (and wliich, it appear*, like the 

 Pimelodiu, is thrown out from the volcanoes of Cotopaxi), but wliich 

 differs in having no adipow fin. 



Atlmblri>iu, Cuv. and Val., consists of but one species, A. Orijcalvii, 

 Humboldt This fish possesses all the characters of the genus Ilruntn, 

 having, like it, the head depressed, the eyes directed upward*, a single 



