PEOF. ST. GEORGE MIVART ON THE 



towards its postaxial margin. The metapophysial ridge is more developed ; and beneath 

 it are two very strong antero-posterior ridges (separated by a marked concavity), outside 

 the pleurapophysial lamella, from the ventral postaxial angle of which a rib-like styloid 

 process extends postaxiad. 



At the preaxial end of the ventral surface of the centrum there is a sharply limited 

 fossa just preaxial to the hypapophysis '. 



In the next vertebra the postzygapophysial process again begins to extend postaxiad 

 beyond the articular surface — as also in Sida and Pelecanus. 



The FIFTEENTH VERTEBRA (Plate LVII. figs. 25-29) is like the fourteenth, and the 

 fourteenth of Sulci, except that the neural spine is a little more developed ; the styloid 

 processes are rudimentary. It differs from the fifteenth of Sula in that the neural spine 

 is so much less developed. The pleurapophysial lamella is wide, as in the fourteenth ver- 

 tebra oiSiiIa. A lateral foramen sometimes leads into the substance of the bone ; only, 

 instead of being situated close to the ventral surface, it is just below the interzygapo- 

 physial ridge. The hypapophysis is largely developed. 



The SIXTEENTH VRETEBRA closely resembles the fifteenth of Sula, only that there is a 

 large, long hypapophysis, instead of a slight median ridge. There is a lateral foramen, 

 as in the fifteenth vertebra. 



The SEVENTEENTH VERTEBRA is Very like the sixteenth of Sula, only that there is a 

 large hypapophysial process, that the lateral canal is still completed below by an osseous 

 bridge, that the hyperapophyses are more developed, and the postaxial articular surface 

 of the centrum more developed transversely. 



The EIGHTEENTH VERTEBRA (Plate LVII. fig. 30) is like the seventeenth of Sula, but 

 that there is a larger hypapophysial process, that the lateral canal is still completed 

 below by a delicate osseous bridge, that the hyperapophyses are more developed, that 

 the postaxial articular surface of the centrum is more extended transversely in propor- 

 tion to its dorso-ventral development, and that the postero-external angle of the centrum, 

 in its ventral aspect, is drawn out into a triangular process of bone, which extends 

 slightly ventrad. From the outer end of the ventral surface of the transverse process 

 a pointed process, more or less developed, extends externad and ventrad ; and sometimes^ 

 there may be, instead of a ventral bony bridge, a long, delicate, movable rib, with 

 both capitulum and tuberculum. 



Cervico-dorsal Vertebra. 



There are generally but two of these (Plate LVII. figs. 31-36). 



The NINETEENTH VERTEBRA is like the eighteenth of Sula, except that there is a long 

 and narrow hypapophysis, that the prszygapophyses are smaller and produced relatively 

 more dorsad, and that the hyperapophyses are drawn out into long, bony, very slender 



' This does not occur till the fifteenth vertebra in 1182 c. 

 As in No. 76. 9. 26. 16 of British Museum. 



