Aug. 10, 1888.] 



SCIENTIFIC NEWS. 



i35 



THE NATURALIST AT THE SEA-SIDE. 



-The Marine Aquarium. 

 very different things may 



IV, 



BY this name very different things may be under- 

 stood. There are the homes of pet anemones, 

 built carefully and well tended, and there are the rough 

 adaptations of household vessels, extemporized by the 

 working biologist. These latter may be soon dismissed, 

 though they are for real study far more important 

 than the L other and relatively permanent sort of 

 aquarium. Nothing is handier for larvse, and Crustacea, 

 and zoophytes, fresh caught and awaiting examination, 

 than a row of tea-cups. The opaque sides and white 

 inside are exactly what is wanted. A can of sea-water 

 carried up from the beach once or twice a week will 

 suffice to change the effete water, and daily aeration with 

 a glass syringe is the only other necessary means of 

 health. Bits of sea-weed are generally desirable, and 

 certain creatures absolutely require mud or sand. 



Though it is true that such hasty provision as we have 

 described is perfectly suited to the collector who has the 

 sea at his doors, the inland naturalist must have his 

 more difficult requirements considered. Everything is 

 now changed by the circumstance that sea-water is hard 

 to procure in large and frequent supplies. With good 

 management, one filling may be made to last for years, 

 and attention must be paid to the only way in which this 

 is possible. The tank should be long, and not very 

 deep or broad. If the ends are square, and the length 

 twice or thrice the depth, the proportions will be found 

 good and convenient. Place the tank in a window. In 

 the bottom fit loosely a number of roofing-slates, each a 

 little longer than the width of the floor, which may form 

 a false bottom, sloping away from the light at an angle 

 of about 25 . Paste a strip of opaque paper on the 

 outside of the glass, so as to darken effectively the space 

 beneath the slates. You have now beneath your 

 aquarium a capacious dark chamber in which life is 

 discouraged. The water, of course, communicates freely 

 with that in the upper chamber, and keeps all cool and 

 fresh. Aerate the tank daily with a glass syringe, and 

 fill up with fresh water as requisite. Two glass bulbs, 

 so weighted that one just floats, while the other just 

 sinks in sea-water, may be bought of the dealers, and 

 these are convenient for indicating the exact amount of 

 water to be added. Failing these, a mark on the side 

 of the tank can be made to do. Rock-work is desirable, 

 but care must be taken to avoid cements which contain 

 red lead or caustic lime. After the tank is complete, 

 but not stocked, it is a good plan to fill it first with 

 fresh water for a fortnight, then with sea-water for 

 another fortnight, and lastly with a second, and, let us 

 hope, final quantity of sea-water. 



In the old days, before Lloyd had shown what was 

 possible and what was not, the enthusiast used to plant 

 his aquarium with Fucus orLaminaria, and then introduce 

 star-fishes, anemones, crabs, and perhaps a fish or two. 

 In a few days the things began to die, and after a fort- 

 night the aquarium was in the condition of a sewage- 

 settling tank. Long experience has shown the impracti- 

 cability of these ambitious ventures. Without a good 

 deal of attention and special precautions, nothing can be 

 trusted to thrive except anemones and such vegetation 

 as springs up spontaneously in the tank. The slates 

 and the glass sides soon turn green with conferva, and 

 this helps materially to sweeten the water. Many 

 species of anemone thrive wonderfully in inland tanks, 



and some of the most beautiful forms can be kept for 

 many years in this way. Don't feed them at all. They 

 require very little, and that little they find for them- 

 selves. One common species (Tealia crassicomis) does 

 not survive long in confinement. Its base is very tender, 

 and it is generally fatally injured in removing it from 

 its native rocks. The emission of young anemones is a 

 frequent event, but the young brood hardly ever pro- 

 duces a well-grown individual. In our own experience 

 no single case of the successful rearing of a young 

 anemone has occurred. 



The anemone-tank, well managed, may be made as 

 gay as a flower-garden. Varied in colour, and form, and 

 texture, some standing up on the bottom, others project- 

 ing from their chosen niches in the rockwork, the polyps 

 delight the eye with their waving tentacles, their gem- 

 like spots, and their discs painted like cathedral glass. 

 It gratifies abundantly that delight in curious and 

 beautiful sights which is a great part of the charm of 

 natural history to glance daily at a richly stocked and 

 well-managed anemone-tank. But there is little to be 

 learnt from it. The creatures whose habits and modes 

 of life are better worth daily observation and study can 

 only be kept alive where a large body of water is 

 mechanically circulated or where loving diligence is 

 spent upon their welfare. It is possible, but not easy, 

 to keep very curious and active marine animals, tube- 

 dwellers, or creatures with strange transformations, alive 

 for months in places far from the sea. The secret lies in 

 isolation of each species and continual supervision. Tiny 

 aquaria of the tea-cup or glass-tube pattern are wanted. 

 Ifthereisa large anemone tank at hand for changing 

 the water daily, so much the better. A neat-handed 

 observer, not afraid of trouble, will find many things 

 possible which the ordinary amateur, enthusiastic but 

 not persevering, cannot be recommended to try. 



If mechanical circulation with a limited supply of sea- 

 water is urgently required, the following plan can be 

 recommended : Arrange three or any larger number of 

 glass bowls on shelves, so as to secure slight differences 

 of level. Connect the bowls by bent tubes, which may 

 act as siphons. Start the circulation with the top vessel 

 full and the bottom one empty. A gentle stream will 

 then traverse the whole series, and the current can be 

 renewed at pleasure by emptying the bottom vessel into 

 the top one. If the system is on so large a scale that 

 difficulty is met with in raising the surplus water to the 

 top, some simple mechanical contrivance, such as a 

 bucket and pulley, may be employed. If muslin strainers 

 are attached to the ends of the siphons a great variety of 

 animals may be kept distinct, each set being confined to 

 its own tank. 



*~P*^i^i^-* ■ 



The Midland Naturalist. Vol. XI., Parts January to July, 

 1888, inclusive. 



Among the many important papers in this journal we 

 may particularly notice that on the function of tannin in 

 the vegetable kingdom, by Mr. W. Hillhouse, F.L.S, 

 The author finds no evidence that it ranks as a food- 

 material analogous to starch, glucose, or oil. 



Mr. W. Jerome Harrison expounds the aid which may 

 be rendered to geology — as, indeed, to other branches of 

 science — by photography, and complains justly that 

 ■" nine out of ten people still think of photography as 

 simply a mechanical way of taking portraits." 



