HARDWICKE'S SCIENCE-GOSSIP. 



37 



the Duke granted that city many privileges, amongst 

 others that of bearing his arms, with his motto ' l Moult 

 me tarde" in old French (I long or wish ardently), 

 which was carved on the principal gate of Dijon. 

 By some accident the middle word was destroyed ; the 

 other two, moult tarde, caused many a smile at the 

 expense of the citizens, and in derision the seneve 

 in which they traded was called mourtarde, a name 

 it has preserved ever since. 



MICROSCOPY, 



ACTINO-CYCLUS BERKLEY!. — I have some speci- 

 mens of this diatom, with reference to which I shall 

 be glad if one of your correspondents will give me a 

 little information. I should like to know, in the 

 first place, whose nomenclature A. Berkley is; and, 

 secondly, whether it is synonymous with any of the 

 species described in the fourth edition of Pritchard's 

 "Infusoria"; if not. where are the specific cha- 

 racters to be found ? — C. V. S. 



Researches among the Sponges. — In the last 

 number of the "Annals and Magazine of Natural 

 History " there appear several important articles on 

 the structure of various kinds of sponges. W. Saville 

 Kent commences with one on " Professor Ernest 

 Haeckel's group of the Physemaria, and on the 

 affinity of the Sponges." W. J. Sollas describes 

 two new and remarkable species of Cliona. There 

 is also a paper by C. Mereschkowsky, on Wagnerella* 

 a new genus of sponge allied to the Physemaria of 

 Ilaeckel. 



Mounting Marine Alg.e. — Mr. H. F. Atwood, 

 of Chicago, gives the following account of his 

 method of mounting alga?, in the November number 

 of the " American Journal of Microscopy." Mr. At- 

 wood advocates the use of salicylic acid, and 

 says — "My process is as follows: by using sea-salt 

 (which can be bought for a trifle at any first-class 

 druggist's) and distilled or rain water, a good sub- 

 stitute for sea-water is obtained ; into this I im- 

 merse the rough-dried specimens of alga?, and in an 

 hour or two they have resumed their natural shape. 

 Now, picking out and clipping off such pieces as 

 are best adapted for mounting, I transfer them to a 

 bowl of distilled water, and wash them clean, and 

 from thence transfer them to a small saucer con- 

 taining a saturated solution of salicylic acid. The 

 shallow cell into which they now go is built up of 

 shellac cement, made by dissolving bleached shellac 

 in Cologne spirits. Cells made of this substance are 

 ready for use twelve hours after being laid on to the 

 slide. I pick up the specimen with forceps, put it on 

 the slide, and fill up the cell with the salicylic acid. 

 I now breathe on the covering glass, and put it in 

 its place, and by the use of blotting-paper absorb the 

 superfluous fluid. A thin coating of gold size com- 



pletes the work for the time being ; in a day or two 

 I lay on more gold size, and afterwards white zinc 

 cement or Brunswick black ; the finish, of course, 

 being a mere matter of fancy. In mounting a piece 

 of alga; having Isthmia parasitic on it, it is almost 

 impossible to fill these diatoms if balsam is used, 

 whereas by the use of salicylic acid every valve will 

 be filled. In some cases the medium I have used 

 has robbed the alga: of its colour, but this occurs 

 but rarely. I have a slide of Ptilota hypnoides in 

 full fruit, the beauty of which could never be brought 

 out except by first immersing the specimen in the 

 sea-water I have referred to. For the study of 

 alga:, direct light should be used, but using dark 

 field illumination is the best way." 



The Quekett Microscopical Club. — The last 

 number of the Journal of this well-known and useful 

 club contains an address by the President, Mr. Henry 

 Lee, F.L.S., and a paper by Mr. W. K. Bridgman, 

 on "The Ordinary Condenser Improved, or 'Cir- 

 cular ' Illumination Superseded." 



Coloured Oysters. — The oysters of the cele- 

 brated Arcachon beds having last summer acquired a 

 peculiar violet colour, the cause has been inquired 

 into by M. Desconst, who finds it was due to the 

 exceeding abundance of the highly-coloured spores of 

 a sea-weed {Rhytiphhva tinctoria). The colouring 

 matter of these spores had been assimilated by the 

 oysters, and retained by them, the extreme drought 

 of the summer months having favoured the operation 

 by reducing the water until it was not sufficient to 

 dissolve the colouring matter. 



The Spore-producing Power of Fungi. — 

 At a recent meeting of the Linnean Society, Mr. 

 Worthington Smith exhibited drawings of Boletus 

 subtome>itosus, and stated that in a specimen five 

 inches in diameter, there are 17,000 pores, or tubes. 

 Each pore when cut across shows 2,000 cells on the 

 surface. The number of surface-cells on the under 

 side of a specimen is 36,000,000. The cells in ar. 

 entire plant are calculated at 615,000,000,000 ; and 

 the number of spores produced by the same specimen 

 are 5,000,000,000. 



Parasitic Alg.l. — Professor Percival Wright has 

 described a new species of Chytridiacea' under the 

 name of Rhizophydium Dicksonii. It was found 

 parasitic in the cells of a sea-weed [Eetocarpus granu- 

 losus), and it is believed that the so-called " utricular " 

 fruits of Harvey, and the "spores" of Kiitzing, are, 

 in the Eetocarpus at least, in reality parasitic 

 Chrytridia. 



Carnivorous Slug. — No doubt the slug which 

 your correspondent in the November number (p. 260) 

 saw feeding on a worm was Testacella Mangel, of 

 which a full and interesting description is given on 

 page S9 of Science-Gossip for April, 1S67. — JV. R. 

 Tate. 



