330 Zoological Collections. 



almost torpid. Their increase is not certainly known in any given time, 

 but must depend upon the quantity of their food ; but it is probable they 

 do not become of the largest size from the smallest in one or even two 

 seasons ; but this, as well as many other particulars, can only be ascertain- 

 ed by new observations and experiments. Bloch states that they grow 

 slowly, and mentions that some had been kept in the same pond fox fifteen 

 years. 



As very large eels after having migrated never return to the river again, 

 they must (for it cannot be supposed that they all die immediately in the 

 sea) remain in salt water ; and there is great probability that they are then 

 confounded with the conger, which is found of different colours and sizes, 

 from the smallest to the largest, from a few ounces to one hundred pounds 

 in weight. The colour of the conger is generally paler than that of the 

 eel ; but in the Atlantic, it is said that pale congers are found on one side 

 of the Wolf Rock, and dark ones on the other. The conger has breathing 

 tubes, which are said not to be found in the other eel. Both the common 

 and the conger eel have fringes along the air bladder, which are probably 

 the ovaria ; and Sir E. Home thinks them hermaphrodite, and that the 

 seminal vessels are close to the kidneys ; but this circumstance demands 

 confirmation from new dissections, and some chemical researches on the 

 nature of the fringes, and the supposed melt. If viviparous, and the 

 fringes contain the ova, one mother must produce tens of thousands, the 

 ova being remarkably small ; and it appears more probable that they are 

 oviparous, and that they deposit their ova in parts of the sea near deep 

 basins which remain warm in winter. This might be ascertained by ex- 

 periment, particularly on the coasts of the Mediterranean. I cannot find 

 that they haunt the Arctic Ocean, which is probably of too low a tempe- 

 rature to suit their feelings or habits ; and the Caspian and Black Sea are 

 probably without them, from their not being foundin the Volga or Danube: 

 these being shallow seas are perhaps too cold for them in winter. From 

 the time that small eels begin to migrate (April) it is probable that they 

 are generated in winter ; and the pregnant eels ought to be looked for in 

 November, December, and January. I opened one in December, in which 

 the fringes were abundant, but I did not examine them under the micro- 

 scope or chemically. I hope this curious problem will not remain much 

 longer unsolved — Salmonia. 



3. On the Luminous Appearance of the Ocean. By Lieut. R. Ingalls. 



While bathing at night, in a southern latitude, I had noticed and ad- 

 mired the beautiful sparkling of the water when agitated or resisted ; but 

 the myriads of bodies of whatsoever sort which emitted these coruscations 

 were alike invisible and impalpable. On one occasion, however, I struck 

 my arm against a small soft mass, which immediately emitted a flash of 

 two or three inches in diameter. But the mass eluded my attempts to 

 secure it, as it was invisible the moment it parted from its accidental 

 contact with my arm. This occurred several times afterwards, and I began 

 to think I perceived a sensation of warmth whenever I struck one of these 



