OSTEOLOGY OF THE DODO. 
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would have had eight pairs of thoracic ribs; and I think this excess of one pair beyond 
the formula in Didunculus to be very probable in the large-bodied, small-winged extinct 
Ground-dove. 
As far as the series of Dodo's neck-vertebre under my observation exhibit such 
characters, the proportion of those with neural spines, or with hypapophyses, or both, 
is the same as in the Colwmbide. In this family, as in most birds, the greater part of 
the series want both processes. The cervical parapophyses, descending to form the 
sides of the carotid canal, do not meet, coalesce, and circumscribe it in any cervical 
vertebra of Goura or Didunculus; and not any of the vertebre of Didus, which I have 
yet received, shows such circumscription of the hemal canal. The majority of the 
cervicals in Didus (those, viz., that lack both neural spines and hypapophyses) are 
broader and more massive in proportion to their length than in the winged Doves. The 
third cervical in Didus has both the above processes, as in Columbidw: the characters 
of the axis vertebra in the same family are closely repeated in that of the Dodo. In 
the Raptores the axis vertebra is shorter in proportion to its length, and a greater pro 
portion of the cervical vertebra at both ends of the series have both neural spines and 
hypapophyses. 
The ribs of the Dodo are as broad, in proportion to their length, as in Doves, but are 
relatively longer in proportion to the dorsal region, encompassing a more capacious 
thoracic-abdominal cavity. The ribs of the Vulture are more expanded than in Didus, 
especially where they afford the extensive attachment to the epipleurals. But I shall 
not dwell further on the comparative characters of this part of the skeleton, as more 
decisive ones of the affinity of Didus are afforded by other parts. 
In comparing the sternum of the Dodo with that of Doves of flight, the first well- 
marked difference is in the adaptive development of the keel in the last (Pl. XV. fig. 2, 
Didunculus), and in the provision for the concomitantly broader coracoids, the grooves for 
which meet and run into each other across the fore part of the bone in existing Colwm- 
bide (Pl. XXIV. fig. 2, 4); consequently the inner or upper wall of the confluent grooves 
forms a median prominence (ib. ¢) at the front margin of the sternum, contrasting with 
the wide notch at that part of the bone in the Dodo (Pl. XVI. fig. 4). The next differ- 
ence, as compared with Gowra and most Pigeons, is the absence of the entolateral 
processes (Pl. XXIV. fig. 3, 7) in the Dodo’s sternum: but Didunculus singularly exem- 
plifies its nearer affinity to Didus by a like absence of those processes; only the sternal 
margins behind the ectolateral processes (ib. fig. 1, h), instead of converging with a 
slight convexity to an obtuse apex, as in Pl. XVIII, describe a concavity, through an 
expansion of the posterior truncate end of the breast-bone. The sternum of Didunculus 
may be said to show one pair of posterior notches (P]. XXIV. fig. 1, f), that of other 
Pigeons two pairs (ib. fig. 3, ff"); but the sternum of Didus, which is relatively broader, 
shows no other trace of the anterior notch (Pl. XVIII. f) than is afforded by the 
rounded angle at which the ectolateral process (/) rises from the bone. Although the 
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