784 



of' ilio Iiorse there is tliiis a cietVlike open coiiimunication of about 

 1 in. 111. long and willi a maxiiniun breadth of 0.3 m.m. After this 

 cleft has closed the central canal attains its greatest depth, viz. 1.33 

 m.m., with a breadth of 0.332 m.m. The fissura anterior has dis- 

 ap[)eared after the rupture, the kidney-form in section gives place to 

 an irregular round shape and afterwards, when the cross diameter 

 of the conus grows shorter, to a pear shape. Finally the anterior 

 portion of the canal is also pointed, whereby the frontal wall is 

 almost readied, but not broken through. The ventriculus terminalis 

 measures about 5.5 mm. 



In two horses the end of the sacral medulla was cut longitudi- 

 nally for a lengtli of 3.5 cm. Here too it is seen that the central 

 canal, before it widens at the end of the conus into a ventriculus 

 terminalis is not everywhere equally wide. Cranially from the 

 ventriculus terminalis more widenings occur, in one case there was 

 even an elongated spindle-shaped widening, 2.5 m.m. in length, to be 

 seen right in front of the ventricle. Since the ventriculus proper was here 

 only 2.8 m.m., it is not impossible that this extreme broadening 

 belongs to it and that the ventriculus in this horse showed a bend. 

 The folds vary greatly in size, the smaller ones protruding at 

 right angles, tiie larger ones at an acute angle, while the longest 

 runs nearly parallel to the comis (fig. 7). The longest which I 



Equus. Fig. 7. 



observed was 5 mm. in length with a breadth of 0.250 mm. In 

 one case a narrow fold was to be seen close to the end of the canal, 

 so that the latter ended here in the form of a pitch-fork. The wall of 

 the ventriculus is much folded, some folds branch off again till the 



whole has a \ery odd appearance 

 ^r^t^f^^^i^ ---'^ ± -^55v^ (fig- 8). The rupture seems to take 

 ^ ^'* ^s:=* ->> place near the end of the ventriculus. 



Behind the ventriculus the conus 

 continues for 0.5 mm. more (fig. 8). 

 Equus. Fig. 8. Neither is the ventriculus obliterated, 



although the epithelium here shows signs of degeneration. 



Especially in the longitudinal sections fine large round cells con- 



