AXIAL SKELETON OP THE PELBCANID^. 339 



tion compared with those of the seventh vertebra that they may be regarded as bemg rather 

 catapophysial than parapophysial. Thus a change takes place here, resembling that de- 

 scribed as taking place in passing from the sixth to the seventh vertebra oi Pelecanus. 



The same contrasts takes place with its angles of articulation with adjacent vertebrae 

 as in the eighth vertebra of Pelecanus. 



The NINTH VERTEBRA, as in Pelecanus, exaggerates the characters of the eighth. Its 

 preaxial part is stiU more, as it were, pressed backwards (postaxiad) and downwards 

 (ventrad). In it, however, the heemal arch is still generally incomplete i. The neural 

 spine is a short strong process, higher and more marked than in the eighth vertebra. 

 Each hyperapophysis appears as a short but strongly projecting process, a line from 

 which to its fellow of the opposite side passes just behind the neural spine. The 

 metapophyses are again more developed, and project sharply dorsad externally to the 

 prsezygapophyses ; and each has two lateral and small prominences (tubercles) below it 

 on the external margin of the process, which, as a whole, is concave postaxially with a 

 median vertical ridge. Considerably ventrad of these tubercles is the small prominence 

 of the parapophysis {p), separated by a narrow groove from the long styloid rib-like 

 process, which is here plainly catapophysial, developing processes mesiad and preaxiad, 

 which may sometimes ^ meet to form a haemal arch, though this is not generally 

 developed till in the next vertebra. Either this ninth vertebra, or else the next, has 

 the largest styloid ribs (Plate LVI. figs. 18-21). 



The TENTH VERTEBRA is like the eighth, except that all the processes are smaller — 

 notably the neural spine and postzygapophyses. The metapophysis still bears the 

 three tubercles on its external margin, and has the vertical ridge behind. There is a 

 hsemal arch which is somewhat antero-posteriorly grooved medianly. The parapo- 

 physes are generally a little less marked than in the ninth vertebra (Plate LVI. figs. 

 22-24). 



The ELEVENTH, TWELFTH, and THIRTEENTH VERTEBRA become slightly shorter succes- 

 sively. They present the general characters of those of Pelecanus, due allowance being 

 made for the shortness of the bones. Here also, as in Pelecanus, the postzygapophyses 

 fail in the twelfth vertebra for the first time in the whole vertebral column to attain 

 the postaxial limit of the hinder end of the centrum. 



The hsemal arch advances preaxiad more in front of the preaxial end of the centrum 

 than in Pelecanus. The three lateral metapophysial tubercles are still conspicuous ; 

 but in the twelfth and thirteenth vertebrae the parapophyses have become undistinguish- 

 ably united with the side of the rib-like styloid catapophysial process. 



The FOURTEENTH VERTEBRA differs from that of Pelecanus in that the haemal arch is 

 suddenly and entirely wanting; and there is even no trace of a catapophysis, the 

 postero-ventral prominence of the bony ring enclosing the lateral vertebral canal 

 being purely parapophysial. 



' Complete in .527b in the British Museum. ^ As, e.g., in No. 779 a in the British Museum, 



VOL. x.^PART VII No. 4. — August 1st, 1878. 3 a 



