783 



heart-shaped form, owing to the conns becoming flatter. As the 

 fissura anterior is still present and the back wall of' the conns rounds 

 otr, the wiiole, on a section, now has the appearance of a kidney. The 

 flattening is a result of the diminishing of the sensory area. The 

 sectional view of the central canal again changes. The posterior 

 portion grows out in a point and before long almost touches the posterior 

 periphery of the conns, the side projections again increase in number, 

 new ones appear among the first, but neither constantly nor symme- 

 trically, while also small projections grow out of the posterioi top 

 which has become flat. The canal now measures at the deepest part, 

 830 m.m., and its maximum breadth is 0.217 m.m. In another 

 horse these measurements were at this place 1.13 and 0.398 m.m. 

 The folds, four, five, and sometimes six in number on each side, 

 vary in size, the longer having secondary smaller ones (fig. 4). 



Equus (Fig. 3) 



Equus (b'ig. 4) 



The conus is still kidney-shaped on section, occasionally a few cells 

 still occur, the posterior zone having no more large cells. After 

 this the canal bieaks through on the posterior side, which break 



Equus (Fig. 5). Equus (Fig. 6). 



can be seen in a series of 62 consecutive sections of 18 fi, for a 

 length of fully 1 m.m. The opening, very narrow at first, gradually 

 widens to a maximum of 0.3 m.m. after which it becomes narrower 

 and the canal closes again, continuing for '/s m.m. nearly to the 

 apex of the conns. 



The ciliated epithelium can still be seen quite intact in many 

 sections as far as the break in the border. In the conus medullaris 



