Zöology; a textbook for colleges and universities . Photograph by J. Arthur ButtonFIG. 134. Cycloid scale of herring, showing transverse radii. A further examination of ctenoid or cycloid scalesshows various interesting features. The surface ismarked with numerous fine lines, which are usually con-centric, but in some cases transverse or are the circuli; they are not growth rings, assome have supposed. There are, however, more or lessdistinct rings called annuli, due to irregularities of square gummed labels, each overlapping one side of the cover glass, or if asecond slide
Zöology; a textbook for colleges and universities . Photograph by J. Arthur ButtonFIG. 134. Cycloid scale of herring, showing transverse radii. A further examination of ctenoid or cycloid scalesshows various interesting features. The surface ismarked with numerous fine lines, which are usually con-centric, but in some cases transverse or are the circuli; they are not growth rings, assome have supposed. There are, however, more or lessdistinct rings called annuli, due to irregularities of square gummed labels, each overlapping one side of the cover glass, or if asecond slide is used, the labels may bind together the ends of the slides;write the data on the labels. After a day or two the scales will be dry, andthe clamps may be removed. The scales will remain in place without furtherattention. 352 ZOOLOGY growth ; these have been much studied of late, becauseit appears that they may be used to interpret the pasthistory of the fish. In the case of salmon,, especially,the study of scales has thrown light on the life hist
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
