224 



Malacep- 



Apotles. 

 An<iuilli. 

 formes. 



ICHTHYOLOGY. 



amining), have invariably been supplied with eels suffi- 

 ciently large to be breeders, during the months I have 

 mentioned. This migratory disposition is not shown by 

 small eels ; and it may therefore be assumed that they 

 remain nearly stationary till they are old enough to have 

 spawn. I have also ascertained that eels are taken in 

 greater or lesser numbers during the months of Novem- 

 ber or December, all the way down the river to the brack- 

 ish water. From thence the young eels migrate, as soon 

 as they are sufficiently large and strong to encounter the 

 several currents of the river, and make their way to the 

 different contributary streams. I have also been able to 

 trace the procession of young eels, or, as it is called here, 

 the ee^/«iV, from the neighbourhood of Blackfriar's Bridge, 

 as far up the river as Chestrey, although they probably 

 make their way as far, or farther than Oxford. So strong, 

 indeed, is their migratory disposition, that it is well known 

 few things will prevent their progress, as, even at the 

 locks at Teddington and Hampton, the young eels have 

 been seen to ascend the large posts of the flood-gates, in 

 order to make their way, when the gates have been shut 

 longer than usual. Those which die stick to the posts ; 

 others, which get a little higher, meet with the same fate, 

 until at last a sufficient layer of them is formed to enable 

 the rest to overcome the difficulty of the passage. A cu- 

 rious instance of the means which young eels will have 

 recourse to, in order to perform their migrations, is an- 

 nually proved in the neighbourhood of Bristol. . Near that 

 city there is a large pond, immediately adjoining which 

 is a stream. On the bank between these two waters a 

 large tree grows, the branches of which hang into the 

 pond. By means of these branches, the young eels as- 

 cend into the tree, and from thence let themselves drop 

 into the stream below, thus migrating to far distant 

 waters, where they increase in size, and become useful 

 and beneficial to man. A friend of mine, who was a casual 

 witness of this circumstance, informed me that the tree 

 appeared to be quite alive with these little animals. The 

 rapid and unsteady motion of the boughs did not appear 

 to impede their progress."' 



•' All authors agree," adds Mr Yarrell, " that eels are 

 extremely averse to cold. There are no eels in the arc- 

 tic regions, none in the rivers of Siberia, the Wolga, the 

 Danube, or any of its tributary streams. It is said there 

 are no eels in the Caspian or Black Seas, but they 

 abound in the Mediterranean ; and M. Risso has de- 

 scribed eight species in his work on the Natural History 

 of the Environs of Nice. There is no doubt, also, that 

 fishes in general, and eels more particularly, are able to 

 appreciate even minute alterations of temperature in the 

 water they inhabit. The brackish water they seek to re- 

 main in during the colder months of the year, is of a 

 higher temperature than that of the pure fresh water of 

 the river, or that of the sea. It is a well-known law in 

 chemistry, that when two fluids of different densities 

 come in contact, the temperature of the mixture is ele- 

 vated for a time, in proportion to the difference in density 

 of the two fluids, from the mutual penetration and con- 

 densation. Such a mixture is constantly taking place in 

 rivers that run into the sea, and the temperature of the 

 mixed water is accordingly elevated."^ As eels are well 

 known to breed in ponds, it may be inferred that their de- 

 scent to the brackish water, though customary, is not in- 

 dispensable. They sometimes attain a great size. The 

 species (or variety) called the sharp-nosed silver eel has 

 been taken near Cambridge of the weight of twenty-seven 

 pounds. 



Some authors make a separate division of the Congers 



{Conger, Cuv.), which chiefly differ from the common 

 eels in having the upper jaw the longest, and the dorsal 

 fin commencing almost over the pectorals. The chief 

 species are the following : Anginlla conger (Plate CCC VI. 

 fig. 3) grows to the size of six feet or more, and is as 

 thick as a man's leg. The conger is found around all our 

 coasts. The skin has a leaden hue above, and is white 

 below, with darker spots along the sides. The dorsal is 

 bordered with black. The teeth are sharp, and when cap- 

 tured the fish is capable of giving very severe bites. The 

 fishermen are stated also to dread injury to their legs from 

 a large conger twining round them. It has been said to 

 attack swimmers by coiling round them, and preying on 

 their bodies. It is voracious, and has not unfrequently 

 been found within the carcasses of dead animals, on which 

 it was evidently feeding. The conger fishery was at one 

 time of some consequence on the Cornish coasts, for the 

 supply of Spain and Portugal. The fish were cured by 

 drying, during which they lost much fat. Anguilla myrus 

 (Rondelet) has a sharp snout, a thin roundish body of a 

 dark colour, without spots, except toward the head, where 

 a few yellowish dashes are seen ; as also a whitish trans- 

 verse band on the occiput, and two rows of small specks 

 on the back of the neck. This species occurs in the Me- 

 diterranean, as do several other small congers, such as 

 A. balearica, mystax, and nigra. The last named lives 

 among the rocks near Nice, and attains to the weight of 

 forty pounds. Its flesh is more esteemed than that cf the 

 common kind. 



The Genus Ophisurus, or snake-tail, differs from the 

 eels properly so called, by the dorsal and ventral fins 

 terminating abruptl}' before reaching the extremity of the 

 tail, which is thus deprived of fin, and ends in a sharpen- 

 ed point. The intestine resembles that of the eels ; but 

 a portion of it extends into the tail, farther back than the 

 anus. The teeth are sharp and cutting. Ophisurus ser- 

 pens is a Mediterranean species, marked by a triple chain 

 of large, dark-brown, oblong spots, on a silvery-white body. 

 It grows to the length of six feet, and is as thick as the 

 human arm. The snout is sharp ; the branchial membrane 

 has twenty rays. Ophisurus guttatus, a handsome spe- 

 cies from Guyana, belongs to this subdivision ; as does O. 

 ophis, the Murcena ophis of Bloch. In some Ophisuri the 

 pectoral fins are small, and sometimes almost impercepti- 

 ble ; a circumstance which assimilates them to the Murce- 

 ntB. Such are O. colubrinus,fasciatus, and maculosus. 



Genus Mur^na, Thunberg. The species were unit- 

 ed by Linnseus to the eels ; but they are distinguished 

 sufficiently by the total want of pectoral fins. Their 

 branchial apertures are minute lateral holes ; their oper- 

 cles are so small, and their branchiostegous rays so slender, 

 and so concealed within the skin, that some able natural- 

 ists have denied their existence in this genus. Their 

 stomach is a short pouch ; and their swimming bladder is 

 small, oval, and placed towards the upper part of the ab- 

 domen. Some of them have the dorsal and anal fins dis- 

 tinctly visible ; some have obtuse, others sharp cutting 

 teeth, and the latter can bite severely. 



The best known is Murcena Helena, or Roman murccna 

 (Plate CCCVI. fig. 2), which abounds in the Mediterra- 

 nean, and was introduced by the luxurious Romans of 

 antiquity, in crystal vases, to the table before being cook- 

 ed, that the guests might admire its variegated skin. 

 This fish is very voracious, and feeds on all sorts of ani- 

 mal matter. The Romans fed them in ponds, and Pliny 

 has recorded the atrocities of Vedius Pollio, who used to 

 punish his offending slaves by throwing them alive to his 

 muraena;. We have seen this fish repeatedly taken at 



Slalacop- 



tervgii 



Apodea. 



Anguilli- 



tbrnies. 



GUaninsii in Natural Ilktory, second series. 



Ibid. 



