346 PEOF. ST. GEORGE MIVABT ON THE 



enclosed dorsally. The hyperapophyses are still longer and more diverging, and con- 

 sequently the postaxial margin of the neural arch more concave (Plate LVII. figs. 1-3). 



There are three hypapophysial processes : — one long median, laterally compressed ; 

 and two small pointed lateral ones, which are really rudimentary styloid ribs. 



The AXIS (Plate LYII. figs. 4 & 5) has its hyperapophyses somewhat less developed 

 than in Sula ; its hypapophysis more convex preaxially, curved so that its tip is almost 

 dorsad ; and instead of the two minute pointed lateral processes in front of the hypapo- 

 physis there are two longer processes connected medianly with the hypapophysis — in fact, 

 two small, but distinct, rib-like styloid processes {ps) which, considered by themselves, 

 might be either catapophysial or parapophysial, but which should rather be considered 

 parapophysial, as they are evidently in series with the parapophysial processes which 

 succeed them postaxially. There is no lateral foramen leading into the centrum. 



The THIRD VERTEBEA (Plate LVII. figs. 6 & 7) is longer in proportion to its breadth 

 than in Sula. The prsezygapophyses look somewhat less dii-ectly dorsad. The spine 

 and hyperapophyses are sharper and more developed. The postzygapophyses are more 

 concave and directed more postaxiad. The styloid rib-like processes are smaller relatively, 

 as well as absolutely, than in Sula, though they have greatly increased compared with 

 those of the axis. 



The FOURTH VERTEBRA differs much as does the third, except that the hypapophysis 

 is less (is much less) dorso-ventrally developed, though more equally so for a greater 

 part of its length antero-posteriorly. 



The FIFTH VERTEBRA is not groovcd beneath, but has an antero-posteriorly elongated 

 hypapophysial ridge but little prominent. 



The SIXTH VERTEBRA is also ridged beneath instead of grooved ; and the neural spine 

 and especially the hyperapophyses and metapophyses are generally more sharply pro- 

 minent ; but the styloid rib-like processes are hardly less developed relatively. 



The SEVENTH VERTEBRA (Plate LVII. figs. 8-11) is grooved beneath, for the first time 

 (as is the fifth of Sula), and (as also that fifth) rudimentary ; catapophyses begin to 

 appear at the preaxial part of the groove. It difi'ers from the seventh vertebra of Sula 

 in that it is grooved beneath narrowly instead of broadly ; otherwise it difi'ers from the 

 vertebra of the same number in Sula as does the sixth ; but the fossa at the preaxial 

 part of its ventral surface is deeper. The styloid rib starts postaxiad from the outer side 

 of the antero-posteriorly grooved lamella of bone which exists on each side of the pre- 

 axial end of the median subcentral groove, and is plainly parapophysial, as it is in Sula. 



The EIGHTH VERTEBRA (Plate L^TI. figs. 12-16) difi'ers from the eighth of Sula in 

 not being pressed back preaxially, and in not diverging widely postaxially ; and the me- 

 tapophyses are not here suddenly increased. The prsezygapophyses still project decidedly 

 preaxiad of the centrum ; and the postzygapophyses ^ diverge but little more than in the 



' These have here their articular surface more elongated and quite extending to the postaxial ends of the 

 processes, -which they do not in the seventh vertebra, and hardly in the seventh of Sula. In Pelecaaus they 



