^00 



(,§. V), the caudal half of S. Til with the cranial half of 5. IV, 

 the caudal half of S. 11 with the cranial lialf of S. J If, and tlie 

 caudal iialf of iS'. / with the cranial lialf of S. II, and in this way 



n.c I 



n c n 



Fig 3. 



ch. — chorda dorsalis ; m. = myotome ; f.i.v = intervertebral fissure ; a.i.s. = arteria 



interprotovertebralis ; A.B. = cranio-vertebral interval ; n.c. I = 1st cervical nerve ; 



n.c. II = 2nd cervical nerve. 



resp. the 4th, 3rd, 2nd and 1st cervical vertebrae will be formed. 



If we call the cranial lialf a, the caudal one h, we can say in 

 general that the /?"' \ ertebra is formed by the fusion of Sn . h 

 with Si^a -\- 1) II \ the «''' vertebra i)as consequently for metamere 

 formula Sn b ^ S{ii -\- 1) a. From the first segment remains now 

 (he cranial half S . Lt, for it remains separated from the caudal 

 lialf of the segment lying cranially from it by the cranio-vertebral 

 interval. 



The conclusion from this demonstration tliat has issued from no 

 other premises tlian from the law of the resegmentation of the 

 vertebral column and from tlie fact, that the cranio-vertebral interval 

 is an intersegmenlai one, must consequently be, that between the 



