PLATANISTA. 535 



rounded knobs that appear on the sides of the caudal vertebrse from the sixteenth 

 to the twenty-second seem to be these processes greatly intensified. 



The transverse process of the first caudal is nearly as strongly developed as in 

 the last lumbar, but in the sixth it has become considerably reduced, and still 

 more so in the seventh, eighth, and ninth, until in the tenth it is little more 

 than a ridge pointing anteriorly. The three first transverse processes are directed 

 backvrards, but those succeeding are slightly curved forwards. On the eighth 

 transverse process the groove for the branch of the caudal artery occurs on the 

 side of the posterior end of the centrum, but, as it is traced backwards, it is seen 

 to be moved more and more forwards until it cuts the transverse process near 

 its middle, as a deep groove. In the fourteenth, the transverse process is reduced 

 to a mere ridge, which is perforated by the arterial groove. In the vertebrae 

 behind this, the transverse processes become enlarged and nodular, like the processes 

 on the inferior aspect of the side already described and from which they are 

 separated by a longitudinally oblique deep furrow. This enlargement begins to 

 show itself in the fifteenth, but is more decidedly marked in the sixteenth, in 

 which vertebra the arterial canal perforates both the processes at their common base. 

 At the twenty-second vertebra the two processes are widely separate, but at the 

 twenty-third there is only one nodular process perforated at its base, and in the 

 twenty-fourth the groove has cut the process in two. 



The oblique processes are long narrow rods in the first six vertebrae, but they 

 become shorter and thicker in the seventh, their characters becoming intensified in 

 the vertebrae succeeding it, tiU at last in the fourteenth they are reduced to an 

 obscure eminence on the body of that segment. The processes of the first caudal 

 embrace the base of the spinous process of the last lumbar, but in the second, third, 

 fourth and sixth they only reach forward to on a line with the posterior margins 

 of the spinous processes in front of them. All the remaining metapophyses stop 

 short of the spinous processes in front of them. 



The spinous processes of the caudal region are all forwardly curved, their hinder 

 margins being convex, and their anterior margins concave, and they are of nearly 

 equal breadth at their bases and extremities in the first five ; but from the sixth 

 backwards they rapidly and gradually diminish in length, their bases becoming 

 narrowed and their extremities expanded. From the eighth backwards they simu- 

 late the form of the chevron bones, and in the ninth, tenth, eleventh, and twelfth a 

 small process is developed at the hinder extremity of their superior margins. The 

 fourteenth has the form and size of the fourteenth chevron, whereas the fifteenth 

 and last is only one-fourth of its size. The nem-al canal in the last-mentioned 

 vertebra is excessively smaU, and the process only occupies little more than one-half 

 of the body, which is deeply grooved behind it by the arterial canal, so that this 

 vertebra is intermediate in its characters between the vertebrae before it with strong 

 spinous processes and those behind it in which these have disappeared. In the 

 sixteenth vertebra, however, the remnants of the laminae are unmistakably present 



