. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. THE TWENTY-RAYED STARFISH. 205 '' Before Ludwig was consulted, this orientation had been adopted for Pycnopodia, owing to the striking bilateral symmetry displayed in the young animals. This symmetry determined that the sixth ray is median anterior between I. and II., and by us has been called "A" (Figs. 4, 5). Ritter and Crocker's diagram (Figs. 4 and 5) agree with Ludwig's (Fig. i). The relative position of ray "A,". FIG. 3. A diagram of the dorsal radial muscles of Pyncnopodia lielian- thoides to show
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. THE TWENTY-RAYED STARFISH. 205 '' Before Ludwig was consulted, this orientation had been adopted for Pycnopodia, owing to the striking bilateral symmetry displayed in the young animals. This symmetry determined that the sixth ray is median anterior between I. and II., and by us has been called "A" (Figs. 4, 5). Ritter and Crocker's diagram (Figs. 4 and 5) agree with Ludwig's (Fig. i). The relative position of ray "A,". FIG. 3. A diagram of the dorsal radial muscles of Pyncnopodia lielian- thoides to show the relation of the primary and secondary rays to the physio- logical anterior end. (Rays I, , /.r-,, /.r4, /.i'3, correspond to I, V, IV, III, II (Fig. 2) respectively) ; rays I-V, rays of the physiological anterior end; these rays, and ray A, are, perhaps, the primary rays ; rays ,, the secondary rays of the left side; rx-rx^, the secondary rays of the right side correspondingly; rays rxs, and /.r,,, the youngest rays, a, anus; Mp, madreporic plate. This sketch is made from the under side of the dorsal muscles. in Pycnopodia, according to Ritter and Crocker, to the five rays of the asteroid ground plan, is between the left and right anterior rays (Figs, i, ; and 4, ) ; the axis of bilateral sym- metry, or Ludwig's orientation line, lies along rays A—IV. ( 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 Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
