220 Queries. 
441.—Fresh-water Sponge.—What is the best way to prepare 
(clean) and mount specimens ? H. M. 
442.—Raising Diatoms.—Will any reader give me a good, 
simple, and reliable method of raising diatoms in the laboratory ? 
V.L. 
Unanswered Queries.—The editor will be glad if readers will 
supply answers to the following queries, which have from time to 
time remained unanswered :— 
324 Rusty Pork and Bacon 388 Violet stones 
335 Double-Pointed Pins 390 Names of Fish 
340 Blue Flame produced by Salt 391 Mounting Parasites 
341 Hoar Frost 392 Snow Crystals 
347 Removing Shells from Brood 401 Poison of Bees, Wasps, etc. 
348 Combustion 403 Card Specimens 
350 Labelling Cabinets 405 Chironomus plumosus 
357 Phosphorescence 406 Swift’s ‘* Stephenson’s Binocular 
362 Double Rose Dissecting Micro.” 
366 Snow plant 408 Carduus Nutans 
369 Fox Earth 410 Absence of Birds 
376 Neophytes 411 Lamp-Chimneys 
379 Section of Flower and Leaf Buds 412 Curling of Paper 
383 Toads 413 Opacity 
384 Hairs of Urtica 414 Forming Cells 
Sale and Exchange. 
Micro-PoLaRiscoPe.—Large quantity of fine slides of brilliant 
crystals for sale; list.—Adlington, Broughton Fields, Worcester. 
Offered, Cone in Cone. Wanted, Hippodium, Plagistoma, Spiriferina, 
Diceras, Melania, Cyrene, Cryptodon, Aturia, Voluta Phorus, Conus, Pleurotoma 
(Pleurotomaria recent), Mitra, Crassatella, Chama, Fulgar Pyrula, Physa, 
Scaphites, Turrilites, Cardita, Typhis, Terebellum, Crania, “Magas, Marsupites, 
Grevillia, Vicarza, Acrodus, Platystoma, Koninkia, Scoliostoma: Any species 
recent or fossil, good specimens.—J Smith, Monkredding, Kilwinning. 
Answers to Correspondents. 
A. P.—Your queries are scarcely of sufficient general interest 
to publish ; we have replied through the post. 
W.—It is quite impossible for us to name the Aphides, as you 
give us no particulars as to where found, &c. 
