. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. 74 Practical Zoology. are reached, the body wall is stronger and cannot be cut with the tips of the scissors without danger of straining them; lift with the forceps almost enough to raise the fish; insert nearly the whole length of one blade so as to cut near the joint of the scis- sors between the pelvic fins. Continue the cut to the narrowest part of the isthmus, where it joins the branchiostegal membranes. 1. Observe that most of the internal organs are in one large cavity, called the body cavity. Its silvery lining is th
. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. 74 Practical Zoology. are reached, the body wall is stronger and cannot be cut with the tips of the scissors without danger of straining them; lift with the forceps almost enough to raise the fish; insert nearly the whole length of one blade so as to cut near the joint of the scis- sors between the pelvic fins. Continue the cut to the narrowest part of the isthmus, where it joins the branchiostegal membranes. 1. Observe that most of the internal organs are in one large cavity, called the body cavity. Its silvery lining is the peritoneum. 2. Near the anterior end of the opening, about opposite the posterior border of the gills, find a transverse partition, the false diaphragm; back of this is the main body caviiy; in front of the partition is the pericardial cavity, which contains the heart. 3. Keeping the fish still on its back, turn now to the posterior part of the body cavity. While holding the edge of the body wall, use the scalpel handle to push aside the internal organs. Note how yielding is the membrane on which the internal organs rest. Beyond this membrane is the air bladder. Be careful not to cut into it until directed to do so. 4. Turn the abdominal wall outward and note the projections made by the ventral ends of the ribs. Begin again at the point of beginning of the first cut, just in front of the anus, and, with scissors, cut the right side of the body wall along the ends of the ribs as above rioted. Continue the cut as far as the bony pectoral arch, just back of the gill opening. Repeat this cut on the left side. Look again at the false diaphragm and its relations to sur- rounding organs, as it will probably be torn in following subsequent directions. Now turn the two flaps of the body wall well out and forward, and tack them down so as to hold the fish securely resting on its back. 5. In the front part of the body cavity is a dull pink or brownish mass, the liver, lying chiefly on
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1903
