104 



SCIENCE-GOSSIP. 



[May 1, 1S6G. 



spines.* We have never observed circulation so as 

 to be certain about it, but Lave often seeu the 

 swarming motion of the particles of eudochrome, 

 believed by many to be connected with some mode 

 of reproduction only partially described, and not 

 understood. Since last December up to the present 

 time (Feb. 21) we have hardly examined one Cos- 

 marium without noticing this peculiarity. At page 

 201 in Science Gossip, Vol. L, will be found a very 

 good account of the mode of reproduction in Cos- 

 murium Botrytls both by cell division and by con- 

 jugation. 



Some desmids are very minute — AnMstrodesmus, 

 for example, which is described as like a tiny bundle 

 of faggots. Others appear as jointed chains enclosed 

 in a glassy tube. Many, also, are so curious that no 

 description without a figure would be intelligible ; 

 but we cannot at the present time enter more 

 minutely into their characteristics. 



"■■/.■ H^Tt^V^ 



Fig. 102. End view of Cosmarium Fig. 103. Aiikistrodesmus? 

 margaritiferum x 250. x 250. 



The name Desmidiacese is derived from a word 

 signifying a chain, and is descriptive of the appear- 

 ance of many members of the family. 



A pleasant writer in " Recreative Science " sug- 

 gests that our jewellers might copy these microsopi- 

 cal plants with advantage to themselves. The idea 

 appear to us to be a remarkably good one, and could 

 they only imitate, in suitable materials, the display 

 of beauteous forms, and delicate colours, so suitable 

 for brooches, clasps, chains, bracelets, &c, which 

 offer themselves in the Desmidiacese, the public 

 would not be slow to appreciate their efforts. 



Before we conclude we will say one word as to 

 the collecting. When in large quantities, they give 

 a green tinge to the surface mud where they lie, and 

 in this case the bottle must be filled with water as 

 nearly as possible at the bottom. Invert it, and 

 when it reaches them turn it on one side, and the 

 contained air will escape while the light mud, with 

 the desmids, will rush in. Another simple plan is 

 to squeeze handfuls of the moss containing them 

 into a large bottle. When the bottle is full of 

 water the light sediment will be found rich in them. 

 Sometimes the hand alone will have to be brought 

 into requisition, to convey such as are known to be 

 attached to the stems and leaves of aquatic plants 

 to the surface. The most elaborate plan of all, 



* We may be under a misapprehension in this, and the 

 specimen of an empty frond we have drawn, may be either a 

 variety, or a totally different species. 



however, is to strain the water containing them 

 through linen, and, when sufficient quantities arc 

 obtained, to remove them from the linen to the 

 stock-bottle. 



We must not dismiss the subject without alluding 

 to the power of motion which the Desmidiacea; 

 possess. Under the microscope several species may 

 be seen to move slightly, and they are believed to 

 retire in dry weather below the surface of the mud, 

 where they dwell while it is soft, and when it is 

 overflowed with water again, to reappear in the 

 light of day, which they seem to love. If kept in a 

 window, the greater part will make their way to the 

 side of the bottle next the light, and numbers will 

 attach themselves in some mysterious way to the 

 glass, at various distances, from whence they cannot 

 be dislodged without a smart jolt. Their small 

 specific gravity, and the mucus in which they are 

 enveloped, perhaps render them important aid in 

 effecting this object. 



Having seen, at a recent meeting of the Micro- 

 scopical Society, Messrs. Powell and Lealand's 

 marvellous exhibition of the circulation in Vallis- 

 meria spiralis under their new binocular and 1-lGth 

 object glass, we were tempted to ask them to 

 permit us to see more of the arrangement. With 

 the courtesy which these gentlemen always display, 

 they invited us to their manufactory, and to our 

 astonishmemt showed the Amician test (Navicula 

 rhomboides) stereoscopically, the markings being 

 resolved into checks in such a manner as we never 

 saw before. 



We then took from our pocket a small bottle con- 

 taining some of the desmids we are describing, and 

 with the help of Mr. Powell commenced an ex- 

 amination of them under conditions which a mouth 

 or two ago would have been considered incredible, 

 viz., an amplification of GOO diameters and upwards, 

 and the binocular relief as satisfactory as the most 

 fastidious examiner could wish. 



S. J. M'Iktibe. 



ANIMALS IN AQUARIA. 



MR, P. H. GOSSE, in his "Aquarium," 2nd 

 ed. 185G, p. 224, tells his readers that if they 

 procure "a few bits of weed- covered rock from the 

 level of low water," and place them in a glass vessel 

 of sea-water, many very interesting creatures will 

 creep out of the interstices of the stones and plants 

 growing on them. I have been in the habit of thus 

 procuring and observing small animals for some 

 years, but I do not find anything so productive of 

 such things as Serpula masses, and the various sub- 

 stances upon which Serpula grow, when dredged 

 from the Bay of Weymouth, iu Dorsetshire. No 



