AXTAL SKELETON OF THE PELECANIDZ. 329 
(though much narrowed transversely) the subcentral antero-posterior groove of the 
lumbo-sacral vertebree (Plate LIX. fig. 3). 
In these three vertebrae the parapophyses become again suddenly and greatly deve- 
loped (especially those of the first sacral vertebra), abutting moreover against the ilium. 
The three parapophyses of each side are united together distally. 
The diapophyses of these vertebre take origin at a higher and higher level (i. ¢., 
more and more dorsad) as we proceed postaxially, so that in the thirty-second vertebra 
they simply diverge from the lateral margin of the summit of the neural arch. 
The coalesced neural spines of these and of the lumbo-sacral vertebra form a rounded 
antero-posterior prominence, convex transversely, running along the middle of the 
dorsum of the pelvis (Plate LIX. fig. 1). 
THE SACRO-CAUDAL VERTEBRA. 
These are generally four; but there may be only three! of these vertebre. They are 
differentiated from those of the last category by the non-union serially and distally of 
their parapophyses together, or with the diapophyses of the sacral vertebra. 
The THIRTY-THIRD, THIRTY-FOURTH, THIRTY-FIFTH, and THIRTY-SIXTH VERTEBRA form a 
series decreasing in size postaxiad, each provided with a parapophysial process (on each 
side), which ascends postaxiad and dorsad to the ilium (Plate LIX. fig. 3). 
The diapophyses proceed externad from the dorsum of the neural lamina, while 
the neural spines are ankylosed together antero-posteriorly as before. A foramen 
is thus formed (apparent on the dorsum of the pelvis) between each serial pair of 
diapophyses. 
As we proceed postaxially, however, the diapophyses spring successively from a 
lower (less dorsad) level as regards the neural spines; so that generally in the last 
sacro-caudal they have again completely coalesced with the parapophyses; and thus 
the antero-posteriorly extended canal between the diapophysial and parapophysial 
elements, which has hitherto existed right through the vertebral column from the 
axis inclusive, here ends and is finally closed. 
Tue CAauDAL VERTEBRA. 
These vertebre may be five? or six in number (more generally six) apart from the 
terminal pygostyle (Plate LIX. fig. 6). 
' As in the specimens Nos. 5274 and 67. 7. 8. 4 in the British Museum. 
2 TI have only found five in the specimen lent me by Professor Garrod, and in a skeleton of P. mitratus 
(No. 70. 3. 30. 1) in the British Museum. Thus in this individual (with but three lumbar vertebra) there 
are but forty vertebre in all, apart from the pygostyle. In the specimens with only three sacro-caudals, there 
were six free caudals, therefore forty-one vertebre in all, apart from the pygostyle. 
