. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. MUSEUM OF COMPARATIVE ZOOLOGY. 305 extend transversely from one side to the other. The muscular saddle is larger than the upper, and is attached to it around its entire edge, so that there is a closed empty chamber between the two ; and the lower edges of all three are united, thus forming a crescent-shaped passage between the lower and muscular saddles. When the muscles of the middle saddle are relaxed, as in death by etherization, this layer is drawn up against the upper one, apparently by atmospheric pressure, and
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. MUSEUM OF COMPARATIVE ZOOLOGY. 305 extend transversely from one side to the other. The muscular saddle is larger than the upper, and is attached to it around its entire edge, so that there is a closed empty chamber between the two ; and the lower edges of all three are united, thus forming a crescent-shaped passage between the lower and muscular saddles. When the muscles of the middle saddle are relaxed, as in death by etherization, this layer is drawn up against the upper one, apparently by atmospheric pressure, and the upper closed chamber is no longer visible, while the. Heart and proximal portion of stolon of young solitary Salpa : b, outer tunic, continued into the outer wall of the stolou ; 1, sinus chambers of stolon; 2, prolongation of pericardium; 4, forming the partition of the stolon ; 3, inner saddle of pericardium ; 4, outer saddle of pericardium ; 5, muscular saddle ; G, arrow showing the course of the current through the cavity of the heart. lower crescent-shaped channel is open throughout its entire length ; as the heart lies in the sinus system, this channel is of course filled with blood. Now it is plain that if one of the transverse muscular bands which compose the middle layer be contracted, the latter must be drawn down at this point until it comes into contact with the upper surface of the lower saddle, as seen in the figure, in which two such points of contraction are shown. This will of course divide. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1871
