26 



W. LlLLJEBORG, 



above which they have a long" processus spinosus, and they are ridged 

 along the middle of the under side of the corpus. There is very little 

 difference between them, except that the 9 th has the largest and the 

 11th the smallest lateral processes. The 10 th (PI. IV. figg. 27, 28, 29) 

 has the corpus, when viewed endways (fig. 29) almost round, but the 

 transverse dimension a little greater than the height. The lateral processes 

 are broad in proportion to their length, and the left appears to stand more 

 straight out from the side than the right, but this latter has been conside- 

 rably corroded in the front border nearer the extremity. The processus 

 mammillares are thin and the processus spinosus, viewed from the side, narro- 

 wer towards the end, even allowing for the circumstance that the anterior 

 border is in that part somewhat imperfect. The foramen spinale is small, 

 and its breadth and height about equal, its form triangular, with an inward- 

 directed flexure in the sides near the upper angle. Dimensions of that ver- 

 tebra: Breadth of corpus 9|"; height of d:o 8|"; length of d:o 9| 7/ ; distance 

 between extremities of lateral processes 2' 8"; length of right lateral pro- 

 cess 12j-"; breadth of left d:o ] ) 6* '; height of vertebra to the top of pro- 

 cessus spinosus 22"; length of processus spinosus about 13"; distance bet- 

 ween external borders of processus mammillares 6". 



In consequence of the differences that appear between the assumed 

 11 th lumbosacral vertebra and that which we take to be the 1 st caudal ver- 

 tebra, ve assume that there have been 3 more lumbosacral vertebrae, situ- 

 ated between the above mentioned, and accordingly that there were 14 ver- 

 tebrae belonging to the lumbosacral region. 



The 1 st caudal vertebra (Pi. IV. figg. 30, 31, 32) differs from the 

 11 th ! lumbosacral in that the corpus is higher and the ridge on its lower side 

 is blunt and terminates at the posterior extremity with a concave surface with 

 two articular surfaces (fig. 31, a) for the processus spinosus inferior (haema- 

 pophyses), that the foramen spinale is less, that the lateral processes are 

 shorter and slightly inclined forward, but inserted lower down on the sides 

 of the corpus, and directed decidedly downwards. Its processus spinosus 

 has probably been shorter 2 ). Viewed from the front end (fig. 32), the corpus 

 has the upper border, making the base of the oval-rounded foramen spinale, 

 straight, but short. The upper lateral borders below this are long and but 

 little curved, so that this end does not display a regularly rounded form. 



') The left is much shorted, being much corroded about the extremity. 

 2 ) It corresponds to the vertebra that by Eschricht and Keinhardt ("on 

 the Northern Whale") has been considered as the last lumbosacral. 



