. The microscope and its revelations. of Laguncula, the chief difference being that a regular cir-culation takes place through the stolon in the one case, such as has110 existence in the other. A better opportunity of studying theliving actions of the Ascidians can scarcely be found than that whichis afforded by the genus Perophora, first discovered by Mr. Lister,which occurs not unfrequently on the south coast of England and inthe Irish Sea, living attached to seaweeds, and looking like an assem-blage of minute globules of jelly, dotted with orange and brown, andlinked by a silvery winding th
. The microscope and its revelations. of Laguncula, the chief difference being that a regular cir-culation takes place through the stolon in the one case, such as has110 existence in the other. A better opportunity of studying theliving actions of the Ascidians can scarcely be found than that whichis afforded by the genus Perophora, first discovered by Mr. Lister,which occurs not unfrequently on the south coast of England and inthe Irish Sea, living attached to seaweeds, and looking like an assem-blage of minute globules of jelly, dotted with orange and brown, andlinked by a silvery winding thread. The isolation of the body ofeach zooid from that of its fellows, and the extreme transparence ofits tunics, not only enable the movements of fluid within the body tobe distinctly discerned, but also allow the action of the cilia thatborder the slits of the respiratory sac to be clearly made out. Thissac is perforated with four rows of narrow oval openings, throughwhich a portion of the water that enters its oral orifice escapes. FIG. 6V) 1. — BotrylltiK riohtreim; A, cluster on the surface of a Fucus ;B, portion of the same into the space between the sac and the mantle, and is thus dis-charged immediately by the atrial funnel. Whatever little j articles,animate or inanimate, the current of water brings flow into thesac unless stopped at its entrance by the tentacles, which do notappear fastidious. The particles which are admitted usually lod»esomewhere on the sides of the sac, and then travel horizontally untilthey arrive at that part of it down which the current proceeds to theentrance of the stomach, which is situated at the bottom of thesac. Minute animals are often swallowed alive, and have beenobserved darting about in the cavity for some days, without any ap-parent injury either to themselves or to the creature which inclosesthem. In general, however, particles which are unsuited for receptioninto the stomach are rejected by the sudden contraction of the mantle(o
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
