30 



SCIENCE-GOSSIP. 



[Feb. 1, I860. 



pursued by her brother in keeping marine animals 

 alive ; for it is well known that, from the latter end of 

 the last century to almost the middle of the present 

 one, Sir John maintained aquaria in his house in 

 Edinburgh. I asked Miss Dalyell, in the first place, 

 whether Sir John chose the vessels in which he 

 maintained his creatures, of any particular form or 

 proportions, so as to obtain, for example, the largest 

 extent of air-absorbing water-surface with the 

 smallest amount of fluid, as would be obtained by 

 the employment of shallow aquaria; and whether 

 he frequently changed the water, or if he depended 

 on the aerating 'effects of growing vegetation ; and 

 whether, to cause more or less growth of algae, he 

 chose various degrees of illumination, according to 

 modern practice, by exposing his tanks to certain 

 aspects of the sky. Also, if he attended much to 

 temperature, and how long he kept the same animals 

 without dying ? To which questions Miss Dalyell 

 answered as follows : — 



" In answer to your inquiries regarding the way 

 Sir John Graham Dalyell kept his marine animals, 

 I will certainly give you all the information I pos- 

 sibly can, by, in the first place, telling you that the 

 vessels containing them were all made of the very 

 finest, clearest glass, wide at the top, just the same 

 width as at the bottom ; they were invariably round, 

 and all sizes — some short, some long, some wider, 

 some not so wide. I cannot remember ever seeing 

 more than one fine specimen in one glass. No 

 marine plant whatever was in the water where the 

 animals dwelt. Sir John fed them himself; what 

 he gave them I do not exactly know, but raw mussel, 

 I know, was one thing. He kept many of his sub- 

 jects eight and ten years alive. He was most par- 

 ticular in giving them sea-water, always taken out 

 of the sea when it was flowing, and he changed the 

 water every morning, often twice a day if he per- 

 ceived the smallest fragment amongst it, wiping and 

 washing the glasses very clean. He got sea-water 

 always twice a week, and sometimes three times. 

 It was carried in an earthenware jar, holding about 

 three or four gallons of water : a person was specially 

 employed for the purpose. Sir John's subjects 

 were always kept in a shelf under the window in 

 his study. It was situated in the north out-look, 

 but whether they were put there for any purpose, 

 I don't know, but I think it was just to put them 

 anywhere out of the way. Sometimes he had a fire 

 in his study and sometimes none. He understood 

 nothing of marine botany. His chief aim was 

 water fresh from the sea, when it was flowing and 

 full of animalculse, and particularly clean vessels. 



" If I can give you any more information on the 

 subject, I will be happy to do it. — I remain, &c, 



"Jan. 2nd, 1860." "E. Dalyell. 



I then wrote again to Miss Dalyell, asking if she 



could give me any dates of her brother's aquarium- 

 keeping, and she replied politely thus : — 



" Your letter of the 18th of January reached me, 

 but it being a difficult task for me to perform — 

 furnishing you with dates — I am sorry to say that I 

 am unable to perform it further than to mention that 

 the first aquatic subject I found was dated in the year 

 1790 ; and, as a curiosity, I desired it to be engraved 

 upon one of the copper plates. It is the River- 

 worm, which forms into a little fly. 



" As you have the work, you will observe a little 

 fly, and beside it a black little worm. The worm 

 ought to have been of the most brilliant scarlet 

 colour. I know as to the Hydra tuba, Sir John was 

 busily engaged about experimenting on it in aquaria, 

 in the years 1800 and 1S03. This is all the informa- 

 tion I can give you. I know very well once every 

 subject was dated, but where these dates are now I 

 cannot tell. " E. Dalyell. 



" Feb. m,im." 



I think '. that these two very interesting letters, 

 bearing on the early history of the aquarium, deserve 

 printing. W. Alfokd Lloyd. 



A EEW WORDS ABOUT SOME 

 ASCIDIANS. 



THERE is one form of marine objects very little 

 noticed by casual visitors to the sea-shore; 

 yet on investigation we may find much of beauty 

 and very much of curious interest among them. 

 These are the Ascidians or shell-less Mollusks, of 

 the different sorts of which a most interesting ac- 

 count is given in the valuable work on "British 

 Mollusca," by Prof. Forbes and Mr. Haidey. 



To attract attention, let us first look at these bits 

 of stone or rock, under our feet, between tide-marks, 

 gbttering like bits of mica slate; plunge them in clear 

 sea-water, and look closely: the shining particles 

 are beautiful little stars, five to nine rayed, but the 

 prevailing number of rays to each star is seven. 

 These are partially imbedded in, and held together, 

 and held fast to the stone, by a dull slimy skin. This 

 linking medium shows us that it is not a single 

 animal which we are looking at, but a commonwealth 

 of beings bound together by common and vital 

 ties. (See fig. 23, which represents " Botryllus poly- 

 cyclas") 



Each star is a family, each group of stars is a com- 

 munity, and each ray of every star is an individual 

 life, containing iu its inmost recesses all the 

 machinery of life, the respiratory gill-plates and 

 circulatory pumps, which a microscopic investiga- 

 tion can discern to be producing minute whirlpools, 

 taking in and throwing out currents of water as 

 needful for the creature's existence. Bound each 

 star, as if marking out the rays more distinctly, is 

 a band of deep purple colour, giving the stars the 



