. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Via. 1-lJ. — Ctenopheran seen from above. S, Bagittal plane ; T, trans verse plane; R, vibratile ijlates ; Gf, gastric canals. In the bilateral arrangement, which is found also in each individual antimere of the Radiata, only one plane, the median j^lci-ne, can be imagined, which passes through the chief axis and divides the body into two exactly similar parts (right and left). These two halves, as opposed to antimeres, may be termed 2mrame7'es. In bilateral animals we distinguish an anterior and po
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. Via. 1-lJ. — Ctenopheran seen from above. S, Bagittal plane ; T, trans verse plane; R, vibratile ijlates ; Gf, gastric canals. In the bilateral arrangement, which is found also in each individual antimere of the Radiata, only one plane, the median j^lci-ne, can be imagined, which passes through the chief axis and divides the body into two exactly similar parts (right and left). These two halves, as opposed to antimeres, may be termed 2mrame7'es. In bilateral animals we distinguish an anterior and posterior end, a right and a left side, and a dorsal and a ventral surface. The unpaired organs are placed in the middle line, on each side of which, in the two halves of the body, are placed the paii-ed organs. The plane which is placed at right angles to the median plane (passing from right to left) and separates the unlike dorsal and ventral halves of the body, is known as the lateral plane. The anti- meres of the Radiata also consist of two parameres, and are therefore bilateral, in that the vertical plane passing through the radius like the median plane divides them into two similar parts. The same groups of organs or similar parts of the same organ may also be repeated in a longitu- dinal direction. This occurs especially frequently in bilatei'al, less frequently in radiate animals (stroLila). The body thus obtains a segmentation, and is divisible into successive sections, the segments or metamer. Fig. 15.—Segmented worm (Polychffite). Ph. pharj-nx; B, ali- mcnt:ny cniial; C, cirrus: F, tentacle. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Claus, Carl, 1835-1899; Metcalf Collection (North Carolina State University). NCRS. London, Swan Sonnenschein
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
