Hardesty, Medulla Spmalis of the Elephant. 133 



into the os sacrum, the canal of which was not opened. The 

 ligamenta denticulata attained a width of from ten to twelve 

 mm. in the cervical region ; in the thoracic and lumbar regions 

 this width varied from six to eight mm. The length of the ca- 

 nalis vertebralis from and including the Ilird cervical segment 

 to the OS sacrum was 175 cm. (The 1st and Ilnd cervical seg- 

 ments were removed with the head). The length of the cor- 

 responding medulla spinalis (dura mater removed) was only 150 

 cm. There was no evidence of the organ having been stretched 

 or distorted. Its weight was not taken. 



The transverse diameter of the canalis vertebralis in the 

 cervical region varied from 65 to 75 mm.; at the level of the 

 thoracic X it was 40 mm. and in the lumbar region the greatest 

 diameter was 60 mm. Corresponding to these diameters, the 

 transverse or lateral diameters of the medulla spinalis were taken 

 at various levels while the specimen was in position. The great- 

 est diameter recorded is 32 mm., and was found in the intumes- 

 centia cervicalis. This was reduced to 22.5 mm, in thoracic 

 III and to 20 mm. in thoracic X. Thence the width remained 

 about the same to thoracic XIII where it became 21 mm. The 

 broadest portion of the intumescentia lumbalis had a lateral 

 diameter of 26.5 mm. 



KoPSCH identified 41 pairs of nervi spinales including the 

 first two which had been removed with the head. These he dis- 

 tributed into 8 cervical nerves, 19 thoracic, 3 lumbar, 5 sacral 

 and 6 coccygeal. 



The lengths of the segments were taken, measuring from 

 the middle of one segment to that of the adjacent. Cervical 

 V measured 32 mm. in length, cervical VIII 25.3 mm. From 

 cervical VIII the lengths increased in both directions, the great- 

 est being attained in thoracic VII which was 68.7 mm. long. 

 Thence to the conus medullaris the lengths gradually decreased, 

 the segment giving off the last coccygeal nerve having a length 

 of only 4. 5 mm. 



The author did not attempt measurements of the lengths of 

 the segments of the specimen at his disposal since it had been 



