152 



DR. B. L0NNBEBG ON THE 



[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 caecum. 



The caecum 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. 



Kg. 7. 



Great and email 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 csecal 

 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, and the fifth and 



