146 



SCIENCE-GOSSIP. 



[July 1, 1866. 



it as fast as they can, dragging it asunder, poking 

 their noses into the limbs and into soft parts of the 

 meat, and making quite a cloud with the commo- 

 tion, till, in a brief space, the shell only remains. 

 Mr. Gosse ascribes much of their hardiness in 

 aquaria to the fact of their keeping much at the 

 surface ; and that no doubt is so, as the top of the 

 water is more aerated than at the bottom — in an 

 aquarium, at any rate ;— and to this must be added, 

 that their vivacity keeps the water in motion, and 

 stirs air into it, and thus health is given by their 

 own liveliness. 



But no stronger proof of the powers of endurance 

 of these fish can be given, than the telling of what 

 our little lot had to go through before I received 

 them. They were caught at Torquay, in Devon- 

 shire, and were sent thence to London by rail, and 

 after having been forwarded across London, were 

 despatched by rail to Southend, in Essex. After 

 being kept there awhile, waiting for the steamer, 

 they were re-transported to London and placed on 

 board a Hamburg steamship, in which they had a 

 sixty hours' rough voyage, and seven hours' extra 

 detention in the Elbe, before arriving here in 

 our gardens in a cab. And yet the loss from the 

 time of leaving Torquay till their deposit in their 

 final home was only twenty per cent., this being 

 occasioned by their having had to be accommodated 

 in some narrow glass jars, of a quart capacity each, 

 on board the steamer from London Bridge till she 

 got out to sea, when some salt water was dipped 

 up, and the fish were placed in a large vessel. 



Another cause of their longevity in confinement 

 is that they so soon make themselves at home, and 

 feed so perpetually. I have had my specimens about 

 a month (it is now January 21th), and during this 

 time they have visibly grown bigger, and they have 

 also in great measure renewed their tails ; for it is 

 curious, and I noticed it years ago, that young 

 mullet, on being first placed in aquaria, are apt to 

 lose their tails from some cause unknown to me ; 

 but I am sure it is not caused by biting one another, 

 nor by any other creature biting them. 



A good account of this fish, by Mr. Yarrell and 

 Mr. Couch, is to be found in Yarrell's "British 

 Eishes," 2nd ed. 1851, vol. i., pp. 231-240 ; and it 

 is there said that when in confinement it will make 

 successful efforts to jump over the edge of the 

 vessel in which it is kept ; but my specimens show 

 no such inclination : they seem quite happy and 

 contented. 



It is well known that the grey mullet will 

 thrive in fresh-water. I have never seen it 

 under such circumstances ; but some months ago 

 one of about eight inches long was caught in the 

 Baltic, in the Bay of Kiel, and was sent me in some 

 of the water from that place, and containing only 

 12 per mil. of saline matters. It arrived in perfect 

 health, but upon being placed in North Sea water, 



containing 36 or 38 per mil. of salts, it could not 

 preserve its gravity, but rolled about from side to 

 side, and sometimes turned belly topmost, when it 

 came up to the water's surface rapidly, and being 

 there, it gradually righted itself, and then descend- 

 ing with an effort, it vainly endeavoured to accom- 

 modate itself to a fluid the specific gravity of which 

 was evidently too great for it. These evolutions 

 were repeated again and again many times, and I, 

 knowingthat sometimes such attempts are successful, 

 and having no vessel large enough to contain in it 

 brackish water, to which it had become accustomed, 

 I left it, and returning in three hours, I found it 

 dead. Had the transition from one kind of water 

 to another not been so sudden, it might have been 

 saved, and gradually got to live in water of the full 

 specific gravity. At about the same time I received 

 from Kiel another consignment, containing some ma- 

 rine fish, consisting of Syngnatlms (pipe-fish), Zoarces 

 (viviparous blenny), Pahemon (prawns), and so forth, 

 and among them were some. other fish which by their 

 feel in my hand I thought were marine perch or basse 

 {Perca labrax). It was in the dusk of the evening, 

 and I could not see well, so I placed these rough- 

 feeling fishes in a marine-tank till I got a light, 

 when I saw them all floating belly upwards and 

 gasping, and found that they were oidy the 

 common perch [Perca fluviatilis) . Then I trans- 

 ferred them to a fresh-water tank, where they soon 

 recovered, and where they still are. Here, then, is 

 an instance of a true marine fish living only in 

 brackish water, and not in fully salt sea-water, 

 and of a true fluviatile fish existing in the same 

 brackish water, and continuing to thrive when 

 suddenly placed in fresh-water without any salt in 

 it. I have had no opportunity of trying whether 

 a mullet from the Baltic would, like the perch 

 from the same place, live in perfectly fresh-water. 



To return to the shoal of little mullets, however. 

 The other animals with them in the same tank are 2 

 large spinous spider-crabs (Maia sqtdnadd), 3 or 4 

 other spider-crabs (Hi/as araneus), about 25 prawns 

 of two species (Palamou serratus, and P. sqidlld), 6 

 black gobies {Gobius niger), 50 or 60 very small 

 double-spotted gobies {Gobius bipunctatus) , about 

 20 small shannies {Blennius pholis), half a dozen 

 each of the three and ten spined fresh-water stickle- 

 backs {G aster osteus aculecdus, and 67. pungitim) — 

 both of these live perfectly well in either river or 

 sea water without any gradual preparation, — and 

 10 five-bearded rocklings {Motella qidnquecirrata) . 

 All of these are predatory in their habits, and, with 

 the exception of the spider-crabs, which are too slow 

 to catch any healthy living fish I am acquainted 

 with— are quick enough in their motions to do 

 mischief to the mullets, which are so peaceable 

 that they very seldom even raise their formidable 

 spiny first dorsal fin, and therefore it becomes an 

 object to protect the mullet (obtained at so much 



