26 SCOTT. [Vol. V. 



specimen before me, so that its height cannot be determined, 

 but it was obviously much better developed than in the llama, 

 and was apparently quite as large in proportion as in the camel. 

 The pedicels of the neural arch are higher than in the recent 

 genera, and the zygapophyses project farther in front of and 

 behind the centrum. The transverse process is a long, stout, 

 depressed plate, which is much more prominent, and has a greater 

 antero-posterior extent than in the living species, and the base 

 of the process is perforated throughout its entire length by the 

 vertebrarterial canal, which is not the case in the camel or 

 llama. Beneath, and slightly in advance of the posterior open- 

 ing of the vertebrarterial canal, there is another large foramen, 

 which, however, merely enters the bone and does not perforate 

 it (PI. II, Fig. 16 vc 1 ). This second foramen is likewise absent 

 in the modern Tylopoda. The inferior lamella is a very large 

 and massive plate, which is longer than the centrum and very 

 different in shape from that of the llama. In the latter the 

 lamella is separated into two portions, an anterior one, which is 

 compres-sed and projects downward, and a posterior one, which 

 is depressed and projects outward. In Pabrothcrium this 

 separation does not occur, the lower margin of the lamella 

 being entire, and giving the whole vertebra an appearance quite 

 like that of the horse. The vertebra is decidedly shorter in 

 proportion than is the case in the llama. The sixth cervical 

 of Camelus dromedaries, as figured by De Blainville, resembles 

 that of the llama in the division of the lamella, while in a spec- 

 imen of C. bactrianus I find this vertebra more like that of 

 PcebrotJierium. 



The seventh cervical is the shortest vertebra of the series, 

 much shorter, proportionally, than in either of the living types. 

 The centrum is broad and depressed for most of its length, but 

 in advance of the transverse processes becomes suddenly con- 

 stricted to form the small and nearly hemispherical anterior 

 face. The posterior face is concave, broad, and low, and shows 

 facets for the first pair of ribs. The pedicels of the neural 

 arch are high, the neural spine thick and inclined forward, the 

 prezygapophyses large, widely separated, and projecting more 

 in advance of the centrum than is the case in the recent species. 

 There is only the faintest trace of the hypapophysial keel and 

 tubercle. In a specimen of this species kindly lent to me by 



