OSTEOLOGY OF THE DODO. 515 
narrow ridge like that (fig. 2, pl. 18, O., ¢5) to which the fifth sternal rib articulates 
in Didus. Admitting, however, that “too much importance must not be placed on this 
character”, and cognizant of instances, like that cited by Messrs. Newton, of five 
articular surfaces on one side, and fowr on the other, yet I am unwilling to suppose 
that the last (in Didus, “sixth”) sternal rib, which terminates below in a point and 
joins the antecedent sternal rib before attaining the sternum, had not its homologue in 
Pezophaps. I quite concur, however, with the observant and conscientious authors of 
the Monograph on the Solitaire that its affinity to the Dodo “is nowhere better shown 
than on a comparison of the sterna of the two forms”?. 
The deeper and more approximate coracoid grooves in the sternum of Pezophaps 
relate to the greater size, thickness, and breadth, especially of the sternal half and 
articular end of the coracoid in that extinct genus. In additional specimens of the 
sternum of Didus, the antero-median depression of the inner surface is more marked 
than in the subject of fig. 2, pl. 18 (O.); but in none has it perforated the bone as 
in fig. 74, pl. 18 (N.). Considering the peculiarity of the configuration of sternum 
in the Solitaire and Dodo—unlike that of any other bird known to me, as to 
Messrs. Newton—the degree of affinity of the two forms appears to be closer than 
would admit of real or intelligible generic distinction. The Solitaire is a longer-legged, 
more active, variety of Ground-Dove, in which the abortion of unused wings had not 
extended to the degree manifested by the larger, heavier, and more sluggish form. 
In the articulated skeleton of the Dodo (Pls. LXIV. and LXV.) I assign twelve 
vertebre to the cervical series, as in the restoration in pl. 15 of my original Memoir; and 
this is the estimate of the number of the cervical vertebre in Pezophaps to which 
Messrs. Newton are led after careful comparison and analysis of the “hundred and 
sixty-one vertebre ” of that extinct bird in their collection’. 
In the unlikely contingency of the disinterment of the bones of any individual Dodo 
or Solitaire which may have lain so undisturbed as to demonstrate the precise number 
of vertebree intervening between the skull and pelvis, the accuracy of our respective 
inductions as to the vertebral formula may be put beyond question. But should it 
prove that there have been one or two cervicals more or less than have been assigned 
to Didus and to Pezophaps, the responsibility as to the former bird will rest with the 
author of the Memoir of 1866, and not with the artist, as to whose figure of the 
*skeleton of Didunculus, in pl. 15 of that Memoir, I must observe that there are plainly 
twelve cervicals given, neither more nor less, succeeded by seven dorsals, of which the 
three confluent ones are the fourth, fifth, and sixth, as in Didus and Pezophaps. The 
remark hazarded by Messrs. Newton in reference to my old, painstaking, and accurate 
artistic fellow-labourer Erxleben, “ that the skeleton of Didunculus in the same plate 
appears to be represented as possessing fourteen cervical and seven dorsal vertebre, 
being altogether two more than we are able to count in the very specimen, now in the 
1 N,, p. 338. 2 N., p. 338. 2 N., p. 382. 
4p2 
