oo 
marked = marked 
Calcaneal groove . wu | Entotrochlearridge. . . . . . a 
Postinternal depression . v Intertrochlear groove . . . . BorB 
Postexternal depression w Posttrochlear depression . . . . y 
Ectogastrocnemial ridge x Ectotrochlear depression . . . . @* 
Postinterosseal ridge y Eitotrochiéay . + fs o> h- & OR 
Ketotrochlear ridge , z Mesotrochled 4 3 4, 4 Rens hoy OE 
Hallucial surface . I Hototoshles. . «es fF OO a 
The “ hallucial facet” is not higher above the entocondyle in Pezophaps than it is in 
Didus; the greater length of the metatarsus is due to elongation of the shaft between 
that surface and the ‘subsidence of the calcaneal process. 
The shorter and stronger metatarsus of Didus indicates more powerful actions of the 
foot, in reference to the greater weight of body to support—perhaps, also, to more 
habitual and powerful applications in scratching up the soil. 
The longer and more slender metatarsus of Pezophaps relates, as Strickland justly 
observes’, to the lighter weight and more active movements of that bird, which seems 
to have preserved its existence to a later period (1735) than the Dodo. 
In a Memoir on the Apteryx, read August 14th, 1858, and printed in the second 
volume of the ‘ Zoological Transactions’ (p. 257), the composition of the metatarsus is 
described as follows :—*‘* The upper articular surface is formed by a single broad piece. 
The original separation of the bone below into three pieces is plainly indicated by two 
deep grooves on the anterior and posterior part of the proximal extremity ; the inter- 
mediate portion of bone is very narrow anteriorly, but broad and prominent on the 
opposite side” (p. 295). This prominence was indicated in subsequent Memoirs as the 
‘‘calcaneal process ;” but it does not form the whole upper end or head of the middle 
piece or metatarsal element. 
In the Memoir on the genus Dinornis I entered, with a view to determine the 
composition and processes of the metatarsal bone, into an analysis of its development, 
and showed, in an immature Ostrich (p. 81), that the head of the middle of the three 
normal metatarsals, which middle bone may be reckoned as that of the third digit, if 
the rudimental metatarsus of the back toe be viewed as the innermost or first metatarsal, 
projects posteriorly beyond those of the other two (second and fourth), and developes 
the chief and commonly sole “‘ calcaneal process.” I also showed that the mid meta- 
tarsal, in its descent toward the toes, changes its relative position to the others, 
coming gradually forward and developing its condyle in advance of, or in a plane 
somewhat anterior to, the condyles of the second (inner) and fourth (outermost) 
metatarsals. 
Messrs. Newton, in reference to the “ calcaneal process,” or the “inner or longest” 
1 Annals and Magazine of Nat, Hist, 2nd ser. vol. iii, 138. 

