-(4-t 



KNOWLEDGE 



NoVEMIiER. mil. 



MICROSCOPY. 



By A. W. Sheppard. I'.K.M.S.. 



icith the assistance of the folluicuig iiiicroscopists : — 



.\rjhurC. P.anfield. Arthl'r Eari.ano. K.R.iM..S. 



The Rev. E. W. Bowei.l. M.A. RrillAui) T. Lewis. F.K.M.S 



Iames BtRTON. Chas V. ROISSELET, P.R. M.S 



Charles H. Caffv.v D. I. ScoiRKfElli. F.Z.S., F.K.M.S. 



C. D. Soar. K.L.S.. F'.R.M.S. 



.\ CASE OF DI.ATOM-WELDIXC;.- 

 graph illustrates the probable fusion of tu 

 taken place during mounting. 

 The slide is an old one by 

 Wheeler, labelled " Test Slide. 

 Dry, Ainphipleura pcUucida. 

 ■iV in. obj," and it is a mixed 

 one. Mr. West, to whom this 

 photograph and others taken at a 

 magniticatiou of X 1000 were 

 submitted, is of the opinion that 

 the smaller valve lying alongside 

 the .4. pclliicida is a Navicnla 

 laci'issiiiiiT. and that the junction 

 is an accidental one. I under- 

 stand that in mounting test 

 diatoms dry, it is the custom, 

 after cleaning the cover glass, 

 to place upon it a drop of the 

 material with a drop of added 

 water, and allow evaporation to 

 take place slowly. The cover is 

 then placed on a piece ot 

 platinum foil or ferrotype plati 

 which is heated to redness, and 

 it is doubtless at this stage of 

 the process that the unnatural 

 union has taken place. 



Obj. 2 mm. H.O.I. .Apochromat 

 X.A. 1-40 (Leitzl, Oc. Compens. 

 X IS. Achromatic Substage Con- 

 denser. .Auxiliary Lens icifh Ins. Screci 

 and Wainwright. '" M " Series. Liliput 



T. W. HUTC 



— The photomicro- 

 o diatoms that has 



^ 



\ 



\ 



; (1) + H.l Wrattcn 

 .Arc lamp. .S Amps. 



HER. M.B., CM. 



spontaneous motion. In reprnduction zoogonidia are formed 

 with two cilia (I-'igure 2 cl, which swim away, but their actual 

 de\elopment into a fresh colony has not been observed. 

 Sometimes when a specimen has been kept in a collecting 

 bottle for a few days, it will be found that all the cells have 

 taken this form and settled on the side of the bottle towards 

 the light, leaving the structureless jelly useless for exami- 

 nation. It is very doubtful if there is more than one 

 well-established species, to which, however, a considerable 

 amount of \ariafion, owing to environment and age. nmst 

 be allowed. My example, in which the cells, from eight to 



ten A< diameter — are arranged 

 in groups of two or four, corres- 

 ponds best with Tctraspora 

 hihrica (Roth), Dr. Cooke 

 gives four species, but is very 

 doubtful about the last of them, 

 and c c r t a i n 1>- the fi r s t , T. 

 bullosa, from the figure — 

 '"British Freshwater .Algae" 

 Plate 5, Figure 1, appears to 

 resemble Monostroiua rather 

 than Tetraspora; in the latter 

 genus the cells should be at 

 least sub - spherical except 

 when undergoing division. 

 Neither does he refer to the 

 " pseudocilia," which, though 

 they are easily overlooked and 

 cannot be distinguished in all 

 cases. West makes of dia- 

 gnostic importance. Who also 

 mentions the occurrence of 

 hypnospores — i.e. resting spores 

 — with thick brown cell-walls, but 

 I have not seen them. Con- 

 siderable importance is attached 

 to the plant from an evolutionar>- 

 point of view — West's " British 

 Freshwater Algae," page 24. 

 from m\' own specimen, b and c are from 

 aboxe book. 



J. Burton. 



~IGfKE 1. 



Figure 1 a is 

 figures in the 



St o- oo (for, O *«R« 





00 c,;^ .. 



»" **«&> 6 00 oat* •^1^*° 





TETR.ASPORA I LINK). —At a recent excursion of the 

 Ouekett Club I came across Tetraspora, an alga perhaps not 

 very frequently met with, and most likely often overlooked 

 when it does occur. It was clinging to some weeds in water 

 about a foot deep near the edge, and appeared as a pale green 

 filmy looking body without any 

 definite outline. There was 

 some difficulty in collecting it — 

 so fragile was it. that an 

 incautious mo\ement with the 

 net at once caused a part to 

 disperse in the water. The 

 plant consists in its young 

 condition of a colourless gela- 

 tinous sac, which later extends 

 in various directions, becoming 

 lobed, torn and membranous 

 finally, it may reach a consider- 

 able size, up to several inches in 

 length. In this are embedded 

 in a single layer the cells which 

 are the living units of the organism. Typically they are globose, 

 of various sizes, according to age, and when mature divide 

 first into two hemispheres, which soon divide again at right 

 angles in the same plane. The four portions, at first somewhat 

 angular, subsequentlv become rounded off, but not usually 

 separating far from each other, cause the grouping into four, 

 which is the noticeable characteri.stic of the plant. The 

 mother cell-wall swells and becomes gelatinous thus increasing 

 the extent of the colony (Figure 2 al. During some period at 

 least of their life these cells are provided with two long 

 " i)seudocilia " (Figure 2 b), but the organism as a whole has no 



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e^' 



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/!/ M (1 



Figure 2. 



T.-VB.\NID.AF. — The cxception.illv fine and hot weather of 

 the past suuuner has resulted in an unusual profusion of insect 

 life, and in no respect has this been so apparent as in the 

 case of the Tabanidae, which, especially abroad, have been so 

 numerous as to constitute a veritable plague. Not only have 



the grey Breeze Hies been 

 remarkably abundant, but the 

 larger species of Tabanus 

 varying in size from one-half 

 inch to one inch in length, 

 beset the traveller wherever he 

 went, even on the higher slopes 

 of the Alpine pastures, above 

 the tree level to a height of 

 o\ er nine thousand feet. F'or 

 the protection of the face 

 and neck a light veil was 

 effective, but the hands and 

 legs were especially exposed 

 to attack, since these flies 

 could alight upon a glove or 

 stocking without being noticed, and could easily pierce 

 the skin through any tight-fitting garment. As regards the 

 Tabanidae, the males appear to subsist on the juices or 

 secretions of plants, but the females are extremely blood- 

 thirsty, and lose no opportunity of attacking both animals and 

 human beings. The mouth organs of the various species are 

 similar, and are of considerable interest not only to the micro- 

 scopist, but also to many others who, whilst suffering from the 

 bites, at least like to know by what means they are bitten. 

 The large fleshy proboscis — or labiniu — common to both 

 male and female, does not greatly diller in shape or structure 



