590 



SALMON. 



regularly to the same river, as to produce the river 

 characters to which we have alluded. The grilses, or 

 young salmon, almost invariably return to the river in 

 which they are spawned ; and it is probable that the 

 full-grown ones return to their last spawning grounds, 

 even though they have been driven from previous 

 ones. The return of the fish to the ground has no 

 connexion whatever with what we are accustomed to 

 call memory ; and its present conduct is not in any 

 way influenced by its past feelings. The circumstances 

 of the present moment and the present place are the 

 only ones which influence it ; and such being the 

 case, we can see no reason why it should return to a 

 former place, if it has once since spawned in another. 

 The return of salmon to a river which has once been 

 wholly deserted by them, must therefore be entirely 

 owing to accident. It is true that they beat along 

 the shores, until they come to the brackish water, to- 

 ward which they ascend, in numbers proportioned to 

 its quantity and its quality. Even after they have 

 cleared the estuaries , and got into the rivers, the 

 quality of the water will make them take one bank 

 in preference to another. Temperature ma)' have a 

 good deal to do in these cases, but it will not account 

 for the whole. They always prefer the river which 

 comes from a lake to that which brings snow water 

 from the mountains, at least in the early part of the 

 season ; but there are some flooding rivers, which 

 have no lakes, in which they appear very early. The 

 Severn is a river of this description. 



There are many cases in which there appear to 

 be three varieties of trout, or even species, if colour 

 and quality were to be admitted as specific differences, 

 in two small streams, and the one formed by their 

 union. If the one branch is clear, with a fine bed, 

 dry banks, and kindly plants on the margins of the 

 pools, then the trout are yellow and beautifully 

 spotted. If, on the other hand, the source is marshy, 

 and the channel contains the coarser aquatic plants, 

 the trout are dark-coloured and coarse, and then, 

 when the two branches unite, the character of the 

 fish is intermediate. All those varieties, which may 

 be found within the space of a few miles, show how 

 much the members of this family are modified by the 

 waters in which they reside, and renders much cau- 

 tion necessary in treating of species and varieties. 



Food appears also to have great influence both on 

 their appearance and their size. The whole family 

 are exceedingly voracious and miscellaneous in their 

 eating, though, of course, the staple food varies with 

 the locality. In the narrow streams the principal 

 food is those insects and larva 5 , chiefly flies, which 

 frequent the waters in such places ; and this is the 

 kind of food which appears to agree best with the 

 species which inhabit the streams at all seasons of 

 the year. Where there are copses, and other shel- 

 ters, for those flies near the banks, the trout are 

 always more numerous, finer, and larger, than in 

 places where the food must consist more of worms 

 and mollusca, and even of small fishes ; and upon 

 trouting streams the anglers know particular spots 

 where there is better sport in one half mile than 

 there is in several miles either above or below. 



It seems, indeed, that the rapidity with which trout 

 grow when they get abundance of flies, is at least 

 one of the natural causes of their ascending the 

 small creeks and streams for the purpose of spawning. 

 The young begin to be able to feed at the time when j 

 the flies are most numerous upon the water ; and 



thus the young prow so fast, that they are, even in 

 the case of the salmon, in a condition for spawning 

 the same year. Those which are more in the brackish 

 water, in the shallows of the sea, or in lakes, appear 

 to feed more upon the smaller Crustacea and mol- 

 lusca, and some of the other invertebrated animals 

 of diminutive size which swarm in those parts of the 

 water, especially at the time when the young of the 

 migrant Salmonida resort to them. They are not, 

 however, confined to food of this kind, for they have 

 not the least objection to a frog, if nothing else can 

 be had ; and the author of this article has sometimes 

 seen a small trout with a frog, too big for it to swallow, 

 hanging partly out of its mouth. 



Most of the species are exceedingly active, though 

 they spend much of the day, if clear, in a state of 

 repose. This great activity requires a corresponding 

 supply of food and degree of respiration ; and ac- 

 cordingly, the feeding and the breathing apparatus 

 are both well developed. The teeth are not of very 

 large size in any of the species, but they are nume- 

 rous. In the trouts, which are the best supplied in 

 this way, there are five rows of teeth in the upper 

 part of the mouth and four in the under part. The 

 middle row of upper teeth is on the vomer, or central 

 bone, and extends the whole length, but the salmon 

 have fewer teeth on this part. The next rows are 

 on the exterior margins of the palatal bones, and 

 extend to the point, having, in all, the shape of a 

 horse-shoe. The remaining rows are on the maxil- 

 lary bones, nearly parallel to the last mentioned, and 

 also meeting in the front. The bones of the lower 

 part of the mouth are so placed as to fall or lock 

 between these when the mouth is closed. There 

 are two rows of teeth upon the tongue, and a sort of 

 groove between them which receives the teeth on 

 the vomer, and the remaining teeth are on the infe- 

 rior maxillary bones. All these teeth, but more 

 especially those upon the vomer and the tongue, 

 have their points directed a little backwards. They 

 are all prehensile teeth, and the middle rows are 

 more strictly swallowing teeth ; but the whole arma- 

 ture of the mouth is such as not to miss a very small 

 object, and to be capable of holding one of consider- 

 able size. They can swallow with great rapidity, 

 and thus can fare well upon minute animals. Their 

 power of swallowing is farther increased by teeth on 

 the bones of the pharynx. Indeed, though all these 

 teeth are prehensile, they have more of them than 

 any other family of fishes. When the mouth is open, 

 the lower jaw seems longer than the upper one, but 

 it shuts with a motion obliquely backwards, so that it 

 closes within the upper one. This motion farther 

 assists in the operation of swallowing ; and perhaps 

 there is no animal that can swallow so often in the 

 same time. The stomach is ample, and furnished 

 with many caeca! appendages. The air-bladder has 

 generally a communication with the gullet at the 

 upper extremity. The gill-lids ad flaps, upon the 

 freedom of action in which the degree of breathing in 

 fishes much depends, are remarkably well made out ; 

 and some of the species, the salmon especially, have 

 more blood in proportion than many other fishes. 



To enter into the details of this very abundant 

 family would require many times the space that we 

 can afford for this article, and even then there are 

 great uncertainties, not only about the species, but 

 about the genera, that have been proposed by some 

 of the writers on. the subject. This arises in great 



