5io 



THE SKELETON OF DOLICHOSOMA. 



smaller than those in the upper jaw. There are indications of a 

 branchial skeleton extending to the sixteenth vertebra. One hundred 

 and fifty vertebrae are preserved, but there may well have been fifty 

 more. In the neck the ribs are simple, in the body they are compli- 

 cated, and in the tail they are absent. The dorsal vertebras have a 

 depressed elongated quadrate form, with a ridge in the position of 

 the neural spine ; the neural arch is constricted in the middle, and 

 terminates at its four corners in zygapophyses. The transverse pro- 

 cesses are compressed, directed downward and outward, and given off 



Fig. 144. 



Ddichosoma longissimum (Fr.), restoration half natural size. From the Coal 



of Nyran. 



from the lower margin of the front of the centrum. The centrum 

 has a circular cup at each end, and the cones unite, so that the noto- 

 chord was persistent. The form of this vertebra may be compared 



