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Show 152 DR. E. L O N N B E R G O N T H E [Feb. 20, wall of the caecum is thicker. The surrounding tract shows some scattered longitudinal folds. Otherwise the internal surface is quite smooth. In the specimens of other species studied for comparison I have not seen such folds in the fundus of the ca?cum. The ca?cum is dilated towards the fundus end, so that its width there is 18 cm. when it lies empty and flat, but at the opening of the ileum it is only 10 cm. The large intestine soon tapers when it enters the spiral from 10 cm., which is its width in the beginning next to the caecum, to a diameter of 4-5 cm. in the spiral coils. It retains that width so long as it is included in the mesentery, but when it leaves this it widens to 8-9 cm. in diameter, and the rectum is still wider, 9-10 cm. When the colon leaves the spiral in the mesentery it becomes covered with fat, distributed in large oval and oblong lumps, which become still more numerous on the rectum. Fig. 7. Great and small intestines of the Musk-ox. If we assume that the first spiral coil (fig. 7) begins at the point where the colon crosses the median line since it has left the ca?cal tract and is bending over to the left side, then the first coil is complete at the number I in the figure, the second at II, the third at III, and the fourth at IV, but at that point the spiral turns and the colon bends back upon itself. The fifth, sixth, and seventh coils (5, 6, and 7 in the figure) are retrograde coils, aud the fifth and |