SCIENCE- GOSSIP. 



shows that the chloroplasts are essential to 

 the reaction. Similar phenomena have long ago 

 been observed in leaves of Dionaea and Drosera : a 

 positive current was found to pass from base to 

 apex of the lamina, and it was determined that 

 the seat of origin of the electromotive force giving 

 rise to these currents was in the upper layers of 

 cells of the lamina and midrib. The movements 

 of such leaves are intimately dependent upon the 

 conduction and liberation of any stimulus applied 

 to them, and a distinct alteration in intensity 

 of the current takes place on excitation of the 

 leaf. 



Double Impregnation. — Of late some inter- 

 esting points have been made out in connection 

 with the phenomenon of " double fertilisation " in 

 Angiosperms. Professor Strasburger, who has been 

 for some time working at this subject, finds in all 

 cases that the process is essential to the formation 

 of endosperm. Double fertilisation is effected as 

 follows : The pollen-tube on reaching the apex of 

 the embryo-sac discharges two male cells, one of 

 which fuses with the oosphere, and the other with 

 the so-called " definitive nucleus " that is present in 

 the embryo-sac after all the changes previous to 

 fertilisation have taken place. This latter nucleus 

 after fusion divides and fills the embryo-sac with a 

 mass of endosperm nuclei. The fact that one of the 

 male cells should fuse with the endosperm nucleus 

 is important, as it shows that both the cells pro- 

 duced by the division of the male generative cell in 

 the pollen-tube are functional, and not, as was 

 formerly thought, only the one of them, the other 

 being absorbed. The process has just been shown 

 (■' Botanical Gazette," xxx. pp. 252-260) to occur in 

 the Compositae (ErigerowC). 



NOTICES OF SOCIETIES. 



Ordinary meetings are marked f, excursions * ; na?nes of persons 

 following excursions are. of Conductors. Lantern Illustra- 

 tions §. 



Geologists' Association. 



June 8.— » Cheam and Epsom. W. P. D. Stebbing, F.C4.S. 

 .. 15.—* Prince's Risborough. W. Hill, F.G.S. 

 .. 22. — * Sections on L. & S. W. Railway. 

 „ 29.— * Stanmore. Clement Reid, F.R.S., F.G.S. 



Lambeth Field Club and Scientific Society. 



June 15.—* Kew to Richmond. 

 ., 22.—* Caterham. Sirs. Rose. ' 



London Geological Field Class. 



June 8.—* Crayford to Frith. Professor H. G. Seeley, F.R.S. 

 ., 15.— » Heme Bay. Professor H. G. Seeley, F.G.S. 

 ,. 22.—* Clandon (for Netley Heath) for Guildford. Pro- 

 fessor H. G. Seeley, F.G.S. 

 „ 29.—* Aylesbury. Professor H. G. Seeley, F.G.S. 



Manchester Museum, Owens College. 



June 1. — f Recent Archaeological Discoveries in Lancashire. 

 Professor W. Boyd Dawkins, F.R.S. 



North London Natural History Society. 



June 6.— t " Reptiles in Captivity." G. H. Wattson. 

 „ 8.— • Bpping Forest. J. E. Gardner. 

 „ 20.— f "A Gossip on the Isle of Purbeck." J. "Wheeler, 



M.C.P. 

 ,. 29.—* Oxshott. L. B. Prout, F.E.S. 



Nottingham Natural Science Rambling Club. 



June 1.—* Hemlock Stone— Geology. J. Shipman, F.G.S. 

 „ 15.—* Lambley Dumbles— Botany. W. Stafford. 

 „ 29.—* Kirkly- Geology. J. Shipman, F.G.S. 



Royal Institution op Great Britain. 



June 1.— t " Epiphytic Plants." Professor J. B. Farmer, H.A.. 

 F.R.S. 

 „ 6. — f " The Chemistry of Carbon." Professor Dewar, 

 M.A., LL.D., F.R.S. 

 8.— f " Epiphytic Plants." Professor J. B. Farmer, M.A., 

 F.R.S". 



Yorkshire Naturalists' Union. 



June 22. — * Scarborough, for Bedale and Yedmandale. 



NOTICES TO CORRESPONDENTS. 



To Correspondents and Exchangers. — Science-Gossip is 

 published on the 25th of each month. All notes or short com- 

 munications should reach us not later than the 18th of the month 

 for insertion in the following number. No communications can 

 be inserted or noticed without full name and address of writer. 

 Notices of changes of address admitted free. 



Business Communications. — All business communications 

 relating to Science-Gossip must be addressed to the Manager, 

 Science-Gossip, 110 Strand, London. 



Editorial Communications, articles, books for review, instru- 

 ments for notice, specimens for identification, etc., to be addressed 

 to John T. Carrington, 110 Strand, London, W.C. 



Subscriptions. — The volumes of Science-Gossip begin with 

 the June numbers, but Subscriptions may commence with any 

 number, at : the rate of 6s. 6d. for twelve months (including 

 postage), and should be remitted to the Manager, Science- 

 Gossip, 110 Strand, London, W.C. 



Notice. — Contributors are requested to strictly observe the 

 following rules. All contributions must be clearly written on 

 one side of the paper only. Words intended to be printed in 

 italics should be marked under with a single line. Generic 

 names must be giyen in full, excepting where used immediately 

 before. Capitals may only be used for generic, and not specific 

 names. Scientific names and names of places to be written in 

 round hand. 



The Editor is not responsible for unused MSS., neither can he 

 undertake to return them unless accompanied with stamps for 

 return postage. 



The Editor will be pleased to answer questions and name 

 specimens through the Correspondence column of the magazine. 

 Specimens, in good condition, of not more than three species to 

 be sent at one time, carriage paid. Duplicates only to be sent, 

 which will not be returned. The specimens must have identify- 

 ing numbers attached, together with locality, date, and par- 

 ticulars of capture. 



EXCHANGES. 



Notice. — Exchanges extending to thirty words (including 

 name and address) admitted free ; but additional words must be 

 prepaid at the rate of threepence for every seven words or less. 



Offered, Segmentina nitida and Achatina acicula. Wanted, 

 Vertigos and others. Lists.— W. Thurgood, 42 Lower Eldon 

 Street, The Groves, York. 



Birds' Eggs. — Wanted, any in exchange for eggs of bullfinch, 

 greenfinch, chaffinch, linnet, wren, long-tailed tit, great tit, 

 hedge sparrow, tree sparrow, house sparrow, pigeon, moorhen, 

 thrush, missel thrush, starling, bunting, chiff-chaff, white- 

 throat. — Miss Vera Bingham, N alder Hill House, Newbury. 



CONTENTS. 



PAGE 



Immature Forms of Rotifer. By Walter Wesche. 



Illustrated 1 



Mosquitoes and Malaria. By E. Brunetti .. .. 2 



The Mycetozoa. By Edgar Saunders. Illustrated .. 4 

 Mosses near Llandrindod W t ells. By Rev. W. H. 



Painter 7 



An Introduction to British Spiders. By Frank 



Percy Smith. Illustrated 8 



Classification of British Ticks. By Edward G. 



Wheeler. Illustrated 11 



Butterflies of the Palaearctic Region. By Henry 



Charles Lang, M.D. Illustrated 13 



Photographic Records of Surgical Operations .. 15 



Books to Read. Illustrated .16 



Notes and Queries. Illustrated 18 



Science Gossip 19 



Astronomy. Illustrated 2i) 



Photography. Illustrated 22 



Chemistry 24 



Microscopy. Illustrated 25 



Botany. Illustrated 29 



Notices 32 



