1889.] MR. W. K. PARKER ON STEATORNIS CARIPENSIS. 173 
articulate with it, and the distal free end is narrow, terete; it is 
ossified, proximally, by a separate centre. The posterior cornua 
are 31 millim. long; they are feeble, rather straight, and the upper 
piece, which is 11 millim. long, has its distal half cartilaginous. 
Ill. The Vertebral Chuin and Ribs. 
The vertebral formula of this bird is as follows :—C. 15, with 3 
pairs of ribs, free, on the left, and 4 on the right side; D.4; S. 13, 
the first with large free ribs, this and the next two, with arrested 
ribs, buttress the pre-ilia; the 13th vertebra not firmly ankylosed 
to the 12th; Cd. 7+4 or 5,=Total 43 or 44. 
The procelous articular facet of the atlas (Plate XIX. fig. 1, at.) 
is somewhat transverse, and this cup is largely notched for the 
odontoid process of the axis (Plate XVIII. fig. 3); not perforated 
as in most of the high arboreal birds. The atlas has no lateral 
passages for the vertebral artery ; its centrum articulates with the 
axis by the normal flat facet. The odontoid process of the axis is 
large (Plate XVIII. fig. 4) ; this bone (Plate XIX. fig. 1, ax.) has 
thick, blunt upper and lower spines, and oblique ascending snags over 
the post-zygapophyses ; a pair of small upper fenestra, and, what is 
very rare in birds, well-formed rib-bars (cr*.) to enclose the canal for 
the vertebral artery ; the articulation of the centra throughout the 
rest of this region is cylindroidal. The 3rd cervical (Plate XIX. 
fig. 1) has also blunt upper and lower spines, lateral fenestrze, above, 
a wide top, and a definite snag over each post-zygapophysis, and a 
rudimentary rib, right and left, bounding the canal for the vertebral 
artery; this part is 3°5 millim. Jong. 
The 4th cervical (Plate XIX. fig. 1) has its sides notched, not 
fenestrate ; it has both upper and lower spines, somewhat larger 
riblets, and spines on the post-zygapophyses. 
The 5th cervical is much like the next four or five; but in this 
strong chain of bones each succeeding vertebra is larger and stronger 
than the one in front of it ; towards the chest they become shorter, 
as well as wider. ‘This 5th bone, like the rest up to the 12th, has 
large riblets; on the 5th, 6th, and 7th these styles reach back 
within 2 millim. of the end of the centrum. None of these vertebree 
have the inferior or carotid canal developed, for the inferior face is 
wide open and gently concave in front; at the middle they are sub- 
carinate, and flat behind, where they broaden out into the apparently 
convex, but really concave, hinder facet. The wide canal for the 
vertebral artery, right and left, is only complete ia the front third of 
each vertebra, and only on the 10th, 11th, and 12th is there any 
rudiment of the oblique bar (or flying buttress) so common in the 
Coccygomorphe, a growth that partially finishes the lateral bony 
wall. I have mentioned that the 3rd has large lateral holes above, 
and that the 4th is notched, and not fenestrate. The 5th also is 
notched on its outer and upper edge; but the hinder margin of each 
notch is developed into an oblique, bony bar, which, running 
forwards, inwards, and upwards, forms by union with its fellow a 
