346 PROF. ST. GEORGE MIVART 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 LVII. 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 VERTEBRA (Plate LVII. figs. 6 & 7) is longer in proportion to its breadth 
than in Sula. The prezygapophyses look somewhat less directly 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 grooved 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 Suda), and (as also that fifth) rudimentary ; catapophyses begin to 
appear at the preaxial part of the groove. It differs from the seventh vertebra of Sula 
in that it is grooved beneath narrowly instead of broadly; otherwise it differs 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 LVII. figs. 12-16) differs 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 preezygapophyses 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 Pelecanus they 
