TEE MAMMALIAN TYPE. 5 



cord, the former occupying its anterior enlargement in the 

 head. Brain and spinal cord together form the cerebro- 

 spinal nervous centre; in addition to this there are found 

 in the ventral cavity a number of small nerve centres united 



FIG. 1. The Body opened from the front to show the contents of its ventral 

 cavity. Zit, lungs; /i, heart, partly covered by other things; le, le', right and l^ft 

 liver 'lobes respectively; ma, stomach; ne, the great omentum, a membrane con- 

 taining fat which hangs down from the posterior border of the stomach and 

 covers the intestines. 



together by connecting cords, and with their offshoots form- 

 ing the sympathetic nervous system. 



The walls of the three main cavities are lined by smooth, 



