28 



W. LlLLJEBORG, 



of the left lateral process, and immediately over the hole through the base 

 of the right lateral process i a short channel directed backward; because 

 the foramen spinale is very small and transversally rounded off, and because 

 the channel along the middle of the under side of the corpus is both broad 

 and especially in its hinder part deeply concave, and there appears also in 

 the middle of the under side a broad transversal groove. The lateral pro- 

 cesses are quite short, but directed forwards, and their hinder angle strongly 

 rounded off. Viewed from the ends the corpus is almost round, with the 

 transversal dimension rather greater than the height. The sides are pretty 

 deeply concave between the edges, both above and below the lateral pro- 

 cesses. The processus maramillares are much decayed, but one can see 

 that they were small and blunt. The processus spinosus is turned back- 

 ward, with the point rounded off and decayed. Dimensions of this vertebra: 

 Breadth of corpus height of d:o 9-f-"; length of d:o 8y"; length of left 



lateral process 2y"; breadth of d:o 5~"; height of vertebra to top of processus 

 spinosus 13-*-"; distance between external borders of processus mammiilares 

 3f-". Right lateral process imperfect. 



In consequence of the great difference in the size of the corpus, as 

 well as of the processes, between our assumed 9 th caudal vertebra and the 

 next succeeding of those discovered, we are compelled to assume that there 

 has been a 10 th , now lost, between them. 



The 11 th — 17 th , 19 th , 20 th caudal vertebrae (PI. VI. fig. 43) display the 

 usual rapid diminution of the hinder caudal vertebrae, as well with respect to 

 the corpus as the arcus and processes, which latter both at last altogether 

 disappear. They also undergo considerable changes with respect to the 

 foramina for the side branches of the aorta. On the three first we find the 

 arcus and decayed remains of the processus mammiilares, and on the two 

 first the lateral processes are distinctly visibles, with the anterior angle for- 

 ming a projecting point. In all three the foramen spinale at the back part 

 diminishes rapidly in size, and in the third is very small. On it (the 13 th ) 

 the only indication of the lateral processes is a bump extending longitudi- 

 nally over each side. The foramina, through which the above-mentioned 

 right and left branches of the aorta pass, have even in the 1 st (the ll 111 ) of 

 these vertebrae their origin on each side of the deep longitudinal canal on 

 the under side of the corpus, and have their openings on the 11 th and 12 th 

 vertebrae above the base of the lateral processes, and on the 13 th above 

 the bump that occupies their place, and over that opening is a bridge, 

 under which the said artery passes. This bridge is narrowest in the 11 th 

 and broadest in the 13 th . In the 14 th these foramina have their upper 



