196 MR.H.E. STRICKLAND ON SOME BONES OF BIRDS ALLIED TO THE DODO. 
brought to light. These are, first, the considerably less development of the inner or 
longest calcaneal process in Pezophaps as compared with Didus. Thus, while the 
antero-posterior diameter of the proximal extremity in the tarso-metatarsus of Didus 
amounts to | inch 4 lines, the same measurement in Pezophaps minor reaches only 
linch 1 line. Again, at the lower extremity we find that the three trochlez are placed 
more nearly in the same vertical plane in Didus than they are in Pezophaps, in which 
latter bird the two lateral trochlez are placed more obliquely and more posteriorly in 
reference to the middle one than they are in Didus. This arrangement seems to imply 
a greater divergence in the lateral toes of Pezophaps than in those of Didus, which 
would probably enable the former bird to run with a speed never attained by the latter. 
The peculiar position of the calcaneal canal on the outer side of the posterior ridge, 
which distinguishes the Pigeons, and the allied group of Pteroclide, from all other birds, 
and which forms one of the strongest proofs of the Columbine affinities of the Dodo, is 
well seen in the bone No. 18. It fully justifies our former conclusions not only as to 
the proximity of Pezophaps and Didus, but as to the position of both these birds, show- 
ing that they are a peculiar and exceptional, yet in all essential points a genuine sub- 
family of that great and isolated family the Columbide. 
The views of ornithic structure, which the examination and comparison of these 
scattered relics have thus gradually developed, render it more than ever desirable to 
search for other portions of the skeleton of the different members of the group Didine 
which once inhabited the Mascarene Islands. Of the two species of Pezophaps from 
Rodriguez, many important parts of the skeleton, and especially the cranium, have yet 
to be discovered. Of the Didus of Mauritius we still want the femur, the tibia, and all 
the bones of the body and anterior extremities, while of the so-called ‘“‘ Solitaire” of 
Bourbon not even a fragment has yet been brought to Europe. After the success, 
however, which has attended similar researches in New Zealand, we cannot doubt that 
an active naturalist, by excavating the alluvia of these different islands, might restore 
the entire skeletons of these extraordinary birds. 
