. The microscope and its revelations. hrough its entire length, andshould be so opened out that its expandedsurface may be a continuation of thatwhich forms the floor of the mouth. Themode of mounting it will depend upon, themanner in which it is to be viewed. Forthe ordinary purposes of microscopic ex-amination no method is so good as mount-ing in fluid, either weak spirit or Goadbyssolution answering very well. But manyof these palates, especially those of themarine Gastropods, become most beautifulobjects for the polariscope when they aremounted in Canada balsam, the formand arrangement of
. The microscope and its revelations. hrough its entire length, andshould be so opened out that its expandedsurface may be a continuation of thatwhich forms the floor of the mouth. Themode of mounting it will depend upon, themanner in which it is to be viewed. Forthe ordinary purposes of microscopic ex-amination no method is so good as mount-ing in fluid, either weak spirit or Goadbyssolution answering very well. But manyof these palates, especially those of themarine Gastropods, become most beautifulobjects for the polariscope when they aremounted in Canada balsam, the formand arrangement of the teeth being verystrongly brought out by it (fig. 709), anda gorgeous play of colours being exhibitedwhen a selenite plate is placed behind the Fobject, and the analysing prism is made Development of Molluscs.—Leaving to the scientific embryologist the large field of study that lies open tohim in this direction,2 the ordinary microscopist will find much tointerest him in the observation of certain special phenomena of. 709.—Palate of Buccl-num undattun as seen underpolarised light. which a general account will be here given. Attached to the gills of fresh-water mussels (Unto and Anodon) there are often found in thespring or early summer minute bodies which, when first observed,were described as parasites, under the name of (.ilnclii,li,i, Inir arenow known to be their own progeny in an early phase of develop-ment. When they are expelled from between the valves of theirparent, they attach themselves in a peculiar manner to the fins andgills of fresh-water fish. In this stage of the existence of the youngAnodon, its valves are provided with curious barbed or serratedhooks (fig. 710, A), and are continually snapping together, untilthey have inserted their hooks into the skin of the fish, which seemsso to retain the barbs as to prevent the reopening of the valves. Inthis stage of its existence no internal organ is definitely formed,except the strong adductor muscl
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
