138 



MUSEUM OF ANIMATED NATURE. 



[Fishes, 



CLASS PISCES (FISHES). 



Bkfork we enter kt lurjfe upon the present cia»s, 

 we mu»t call attention to a sinsfular form, I^piilo- 

 •iren, xvhich by »ome naturalists is referred to the 

 Perennibranchiate Amphibia, and by others to the 

 fishes. 



It was in the year 1837 that Professor Natterer 

 obtained two specimens, one found in a swamp un 

 the left bank of the river Amazon in South America, 

 the other taken in a pond near Borba, on the river 

 Madeira, a tributary to the Amazon. The descrip- 

 tion of these was published in the 'Annals of the 

 Museum of Vienna,' under the title of " Lepidosiren 

 paradoxH." In the same year an allied species wag 

 presented to the Koyal College of Surgeons by 

 Thomas C. B. Weir, Esq., toitether with a smaller 

 dried specimen enclosed in indurated clay baked 

 hard in the sun ; it was brought from the river 

 Gambia in Africa : and under the generic title of 

 Protopterus was described by Professor Owen in the 

 MS. catalogue of the Museum R. Cott. S., and more 

 fully in the ' Linnean Trans.' (vol. xviii. pt. 3, p. 327), 

 under the title of Lepidosiren annectans, the generic 

 term proposed by Dr. Natterer being adopted. Of 

 this species from Gambia Fig. 2370 is a represen- 

 tation. 



In both species the body is fish-like, and covered 

 Mrith scales ; there are mucous pores and ducts upon 

 the head, and a series of pores around each eye : 

 whence the lateral line, seen in fishes, commences; 

 the muzzle is obtuse ; the branchial apertures are 

 narrow vertical slits; the eyes are small; the nos- 

 trils are situated at the under part of the upper lip 

 (which is fleshy), and lead, as m fishes, to two sacs, 

 which have no communication with the mouth, and 

 are not respiratory organs ; there are two slender, 

 sharp-pointed, recurved teeth in the intermaxillary 

 bone, and the alveolar border of both the upper and 

 lower jaws is armed with a strong trenchant dental 

 plate, soldered to the bone, and divided at the 

 middle line, so as to form two distinct portions above, 

 and two below ; each of these portions is twice 

 indented, so as to present three angular acute pro- 

 cesses, adapted for piercing; and the strength of 

 the jaws, and size of the muscles which work them, 

 prove that they are efficient instruments. There 

 are no palatal teeth. The limbs are represented by 

 four tentacular appendages, many-jointed in the 

 African species, not jointed in the American. A 

 dorsal fin, supported by numerous soft elastic trans- 

 parent rays, commences about one-third of the dis- 

 tance from the head, and runs to the extremity of 

 the tail, which is furnished underneath with a simi- 

 lar fin ; but there is no expanded caudal fin as in 

 fishes generally. The skeleton is partly cartilagi- 

 nous, partly bony, and the osseous portions are of a 

 green colour as in the Gar-fish. 



With branchiae or gills approaching in structure 

 those of the Perennibranchiate amphibia, the Lepi- 

 dosiren also possesses lungs, and, as there is reason 

 to believe, breathes, occasionally at least, atmos- 

 pheric air. In some specimens of the African Le- 

 pidosiren two minute tentacles accompany each of 

 the pectoral or anterior ones. The heart possesses 

 a double auricle in the South American species, and 

 the skeleton is more cartilaginous. 



The Lepidosiren paradoxa from South America 

 attains to a considerable size ; one of Dr. Natterers 

 specimens measured upwards of three feet in length, 

 and the other nearly two. 



The Lepidosiren annectans from the Gambia 

 does not much exceed a foot in length. The speci- 

 men, a female, described by Professor Owen in the 

 ' Linn. Trans.' vol. xviii. part 3, measured twelve 

 inches eight lines. From the fisli-Iike contour of 

 these animals we may easily form an idea of their 

 progressive motion through the water, and it is pro- 

 bable that the tentacular appendages may enable 

 them to raise themselves upon aquatic plants, or 

 even to crawl up the banks of the pond or river. 



In a notice respecting these singular creatures by 

 Sir W. .lardine, in the ' Ann. and Mag. of Nat. 

 Hist.,' March, 1841, p. 25, he says, in reference to 

 the African species: — " If the structure of this ani- 

 mal is remarkable, so also are some habits in iis 

 economical history ; but we have to regret that our 

 history on these points is still very imperfect." 



Miss Weir, in allowing us to examine the speci- 

 mens of the fish, accompanied them with the follow- 

 ing note, and a piece of the hard clay, alluded to in 

 the ' Trans. Linn. Soc.,' bearing the impression of 

 the animal, as if it had lain for some time imbedded 

 in it, and with the earth in such a state as to allow 

 the form of the cast to be retained. " Fish taken in 

 the summer of 1835 on the shore of Macarthy's 

 Island, about three hundred and iifty miles up the 

 river Gambia. They were found about eighteen 

 inches below the surface of the ground, which, du- 



I ring nine months in the year, is perfectly dry and 

 I hard ; the remaining three months it is under water. 

 I When dug out of the ground and put into water 

 I the fish immediately unfold themselves and com- 

 I mense swimming about. They are dug up with 

 sharp stakes, and are used for food." 



A specimen, folded up and enveloped in leaves, 

 was among those examined by Sir W. Jardine. It 

 seemed, he says, "to have been rolled up in dried 

 leaves, or in leaves which might have accumulated 

 at the bottom of the inundated ground ; several 

 adhered to it, and were kept in their place by 

 j means of a large supply of mucus, which still in- 

 ; vested the specimen, and may serve as a provision 

 to assist in preserving life during the torpidity or 

 hybernation of the animal." 



From these anomalous beings we pass on to the 

 true Fishes. 



The study of fishes, termed Ichthyology ("x*"*. 

 a fish, Ao^oj, a discourse or treatise), is not only 

 very interesting, but very important. Of all the 

 clajises of vertebrate animals, there is not one which 

 affords so great a number of species useful as food 

 to man. Nor is the supply scanty : they are drawn 

 by millions from the deep; the work of the fisheries 

 gives employment to thousands ; the amount of pro- 

 perty involved is enormous ; and for the promotion 

 and protection of this branch of traffic, legal enact- 

 ments have been enforced, and societies incorpo- 

 rated. Without going into long details, let us look 

 simply to the British Fisheries, and give one or two 

 instances of the national importance of this source 

 of wealth. We will take the herring, a fish used 

 both in a salted and fresh state. 



endintf Cured 



April d. Barrels. 

 1832.....362,fiti0 

 1833. ...416,964 

 1834. ...394,916 

 1835. ...277,317 



1636 497,610 



1837 397,737 



Branded 

 Barrels. 



l;->-,839 

 168, -259 

 178,(100 

 85,079 

 192,317 

 114,192 



Exported 

 Barrels. 

 217,499 

 220,684 

 272,093 

 158,805 

 273,393 

 189,265 



The number of boats and fishermen and other 

 persons employed in taking, cleaning, curing, and 

 packing cod and herrings, in each of the six years to 

 April, 1837, were as follows: — 



V T«K.. Number Number Total 



Year. iriS^ <>' F'«''- of Coopers, Number 



.ermen. Curers, Sec. employed. 



1832.. ..11,059 49,164 31,402 80,566 



1833 11,008 48,181 33,274 81,455 



183-1 11,284 49,212 33,054 82,266 



1835.... 11, 359 49,462 32,861 82,323 



1836.. ..11, 427 49,720 37,178 86,898 



1837 11,494 51,907 34,626 86,533 



During a favourable season 100,000 mackerel are 

 brought to Billinsgate market every week; we say 

 nothing of soles, turbot, whiting, haddocks, salmon, 

 eels, &c., &c. ; for want of space prevents our 

 entering into details. But to turn from the fisheries 

 of our own and other European nations, to liow 

 many tribes of savage people do not the magazines 

 of the ocean afford the almost exclusive means of 

 subsistence ? Look, for instance, at the natives of 

 Nootka Sound, and see the rude cabin stored with 

 fish, dried and smoked, which with the roe pre- 

 pared, and forming what Cook called their " bread," 

 constitute their winter diet. (Fig. 2371.) We 

 might easily add other instances, but it is needless ; 

 they will suggest themselves to our reader. 



Tenants of the waters of our globe, the organiza- 

 tion of these animals expressly fits them for their 

 liquid element. They are clothed neither with hair 

 nor feathers, but with smooth scales, often beauti- 

 fully bright and delicate, giving uniformity of surface 

 to a compact contour, admirably adapted for pro- 

 gress through the waters. Some, it is true, have a 

 hard osseous envelope, as the Ostraceans ; and others 

 are arrayed in a panoply of spines, as the Tetrao- 

 dons, and Diodons, which remind us of the hedge- 

 hog. There are some also, as the eel, the cod-fish, 

 shark, &c., which have the skin naked, smooth, 

 and slippery. As is the case with terrestrial ani- 

 mals, they vary in their habits and powers of loco- 

 motion: some move slowly along, others cleave the 

 waves with the velocity of an arrow, bear up the 

 rapids, and clear the falls with wonderful energy. 

 Many persons regard the fins as the principal 

 organs of locomotion in fishes, but these, in fact, 

 are principally used as balancers of the body, as 

 agents in turning the direction of the animal's course, 

 or of guiding it as it swims along. It is the tail or 

 elongated muscular extremity of the fish, tipped 

 with a broad expanded web or fin, which constitutes 

 the efficient organ of locomotion. The fish sculls 

 itself along by rapid strokes from side to side, as 

 may be seen by disturbing one of these animals 



wWl« at rest and watching its actions. It is by the 

 movements of the same organ, only more violently 

 exerted, that the fish leaps out of the water, and 

 springs at insects, or clears the waterlall ; and we 

 may further observe that it is only in such fishes as 

 have the tail muscular and powerful, and the body 

 compactly shaped, that this faculty of leaping exists. 

 The large-headed, slender-tailed cod-fish cannot 

 leap, but the salmon and trout will spring several 

 feet above the surface of the water. The use of the 

 fins as balancers was proved by the experiments 

 of Boulli, who observed, that when both the ventral 

 and pectoral fins of fishes were cut off, all their mo- 

 tions were unsteady, and they reeled from right 

 to left, and up and down, in a very irregular man- 

 ner. 



In adverting to the movements of fishes, we must 

 here notice that internal sac generally known under 

 the name of the swimming bladder. This consists 

 of a reservoir of air placed beneath the spine, and 

 varying in form and size in different species ; in some, 

 as ihe perch, it is simple, and closed at both ex- 

 tremities; in the carp it is large, and divided into 

 two portions: sometimes a communication exists 

 between this sac and the gullet, or, as in the her- 

 ring, between it and the stomach. The gas with 

 which this sac is filled is generally found to be 

 nitrogen; but in fishes that live at a great depth, 

 the gas has been ascertained by MM. Configliac- 

 chi and Biot to be chiefly oxygen. It is, according 

 to the opinion of most naturalists, by the compres- 

 sion of this s.ac that the fi.-ih is enabled to sink, the 

 specific gravity of the body being altered by the 

 degrees of contraction or expansion to which the 

 sac is subjected. In many fishes, however, this 

 swimming bladder is wanting, as in the red mullet 

 and the mackerel. Mr. Yarrell says, that one-fourth 

 of the fishes known are without air-bladders, and that 

 two-thirds of the other three-fourths have the air- 

 bladder entirely closed, having neither canal nor 

 aperture for external communication. Fig. 2372 

 represents the Swimming Bladder of two fishes. — 

 A, the Dace; a, the Stomach; b, the Swimming- 

 bladder: B, the Conger-Eel; a, the Stomach; 

 b, the Swimming-bladder. 



We need scarcely observe that fishes respire 

 through the medium of water, by branchiae or gills 

 forminga series of vascular fringes supported by bones 

 termed the branchial arches, generally four in num- 

 ber on each side. The water is taken in through 

 the mouth and passed out over the gills so as to 

 lave them thoroughly and oxygenate the blood. 

 The gills are covered by a flap called the opercu- 

 lum or gill-cover, composed of four pieces, the 

 priEoperculum, the operculum par excellence, the 

 subopeiculum, and the interoperculum ; besides 

 these, there is a membrane supported by a row 

 of slender bones springing from each branch of 

 the OS hyoides, so as to clo.se the great fissure 

 beneath. This membrane is called the branchi- 

 ostegous membrane, and the slender bones the 

 branchiostegous rays. The heart consists of one 

 auricle and one ventricle. 



The teeth of fishes in general are organs of pre- 

 hension, and vary in form, number, and situation ; 

 often the whole of the inside of the mouth is 

 armed with them; not only are the jaws furnished 

 with them, but the palate, the pharynx, and the 

 tongue itself. In the carp tribe, there are no teeth 

 in the jaws, but there are pharyngal teeth, so dis- 

 posed as to work upon a broad three-sided plate, 

 supported by the basilar bone at the base of the 

 skull, and by this is the aliment bruised before pass- 

 ing into the stomach. There are no salivary 

 glands, and the sense of taste is not acute. The 

 organs of smell are simple cavities which have no 

 communication with the mouth, and are lined with 

 a pituitary membrane variously folded, evidently to 

 increase the extent of sentient surface over which 

 the fibrils of the olfactory nerve are spread. 



The sight of fishes is generally quick and 

 accurate, and the eye is expre.ssly organized for 

 acjuatic vision; the crystalline lens is large, dense, 

 and globular, approximating to the flat cornea, the 

 a(iueous chamber being very inconsiderable, and 

 the aqueous humour only sufficient to allow the 

 free suspension of the iris. There are no eyelids. It 

 cannot be doubted that fishes hear ; they have, how- 

 ever, no external auditory apparatus, nor a tympanic 

 cavity, but a labyrinth, viz. three semicircular 

 canals, communicating with a vestibular cavity 

 filled with a transparent glairy fluid, and enclosing 

 certain hard bodies called otolitlies, generally ihree in 

 number, suspended by delicate filaments. We have 

 said that fishes are r.sually covered with scales, dif- 

 fering in size and arrangement; one row of scales 

 along each side, forming the lateral line, is generally 



