SCIENGE-GOSSIP. 



343 



Flotation of Foraminifeba.- — The following 

 details from my note-book on the subject of 

 Mediterranean sponge-sand will perhaps interest 

 your readers, and may help to explain the failure 

 {ante, p. 286) to make successful floatings from 

 such small quantities as from one quarter of an 

 ounce to one ounce of material used by Dr. Bryan. 

 My figures will probably hold good for any average 

 sample of the fine or common sponge-sand, such as 

 may be readily procured from a chemist or sponge 

 merchant. There is also a coarser Mediterranean 

 sponge- sand, evidently from extremely shallow 

 water ; but this is of infrequent occurrence, and 

 difficult to obtain. My object was to ascertain 

 roughly to what extent foraminifera contributed to 

 the formation of this deposit, which must cover 

 large areas on the shallow southern coasts of the 

 Mediterranean. For this purpose I passed a 

 quantity of the sand, weighing in all 2,300 grains, 

 through a succession of sieves, with the following 

 results: (a) Passed through sieve No. 17 silk gauze 

 of 160 meshes to linear inch (879 grains). This 

 formed an impalpable sand, composed of fine silice- 

 ous and calcareous particles, averaging abovit one 

 three-hundredth inch in diameter. It contained 

 no recognizable remains of foraminifera, except 

 a few primordial chambers, although the cal- 

 careous portion— about one-third of the whole 

 — was doubtless due to their disintegration. 

 (6) Passed through sieve of copper wire gauze, 120 

 meshes to linear inch (753 grains). — A similar but 

 coarser sand, averaging one two-hundredth inch 

 in diameter. Foraminifera were numeroiis, but 

 always fragmentary or immature. (c) Passed 

 throiigh sieve of brass wire gauze, 80 meshes to 

 linear inch (340 grains). — A fine siliceous sand, with 

 an admixture of about 20 per cent.calcareous matter, 

 chiefiy f oraminif erous. Speciniens,mostly immature 

 and broken, but including perfect specimens of the 

 smaller genera, Bolivina, Biscorbina, Nonionina, &c. 

 (d) Passed through sieve of brass wire gauze, 40 

 meshes to linear inch (290 grains). — Similar to the 

 last, but coarser. The foraminifera chiefly small 

 specimens of Peneroplis, Polystomella, Miliolina, and 

 similar shallow- water forms ; a large percentage 

 of them broken, and, with the exception of the 

 Miliolidae, all poor floating forms, (e) Eetained 

 in sieve of 40 meshes to linear inch (23 grains). — 

 Almost entirely calcareous, and principally com- 

 posed of foraminifera, many broken and more or 

 less worn. Peneroplis, Miliolina, Spiroloculina, and 

 rolystomella were the predominant forms. Loss 

 in sifting, 15 grains. Total, 2,300 grains. Now, 

 there are two facts worth noting in connection 

 with these figures : first, the large proportion of 

 1,632 out of 2,300 grains entirely destitute of 

 foraminifera, a further 340 grains containing but 

 very few specimens ; second, the entire absence 

 of the Lagenidae and Globigerinidae, which, of 

 all foraminifera, are the readiest to float. I may 

 say that I have never tried to make floatings from 

 sponge sand, and should think it about as difficult 



a material to work with as it would be possible to 

 obtain. At the same time, I have no doubt that 

 with patience and a sufficient amount of technical 

 skill, such a thing would be possible ; although, 

 for the reasons I have already mentioned, the 

 percentage of floats obtained would be very small. 

 Dr. Bryan should have removed the finer portion 

 (a and h) by means of sifting, as these minute 

 particles, being practically of no weight, are more 

 subject to capillarity than the forams. It is 

 possible to prepare fioatings from even a quarter 

 ounce of material, but, unless for special reasons, 

 I should not attempt it, as the amount of time and 

 trouble spent on the work would be more than 

 svifficient to examine and pick over the material 

 under a microscope. The method I employ in 

 siich cases is to place the material in a tiny 

 beaker or evaporating dish, removing the floats 

 with ungummed cigarette papers, to which the 

 forams adhere when they are rested on the 

 surface of the water. I then dry the papers, and 

 brush the floatings off into a tube with a dry 

 sable brush. If a large quantity of sand is poured 

 into water at one time, there would, of course, be 

 considerable risk of the floatings being carried 

 down with the sand and covered ; hence I gene- 

 rally add the sand a spoonful at a time, removing 

 the forams continually as they rise. I am afraid 

 a description of my methods and apparatus would 

 take up too much space, but if the Editor thinks 

 it would be of interest to the readers, I will 

 describe them with pleasure in a future paper. — ■ 

 A. Eaeland, 28, Glenwood Road, Catford, S.E. 



Parasite op Humble Bees. — Whilst cycling 

 in Wiltshire last autumn, at the close of a very 

 hot day, I noticed a strange lo )ki ng creature 

 crawling across the road, apparently helpless. 

 On closer examination I found it to be a humble 

 bee, Psithyrus rxipestris. It was completely covered 

 with hundreds of parasites, which accounted for 

 its curious light brown appearance. Under the 

 microscope the' parasite was seen to be one of the 



mites Gamasus coleoptratorum. They are by no 

 means uncommon and are well known to infest 

 both the humble bee and dung beetle. I 

 have found them on the last named insect 

 as recently as January of this year. A very 

 full description of this and allied species 

 will be found in the Linnaean Society's Trans- 

 actions. The accompanying photo-micrograph is 

 taken from a specimen mounted in Canada balsam. 

 — F. NoAD Clarke, Paddington Infirmary, London. 



Journal of Applied Microscopy. — With the 

 beginning of this year Volume II. of the "Journal 

 of Applied Microscopy" commenced. It is a monthly 

 magazine published by the Bausch and Lomb 

 Optical Company, Rochester, New York. 



