34 
phaps. The calcaneal cond is smaller. The tendinal groove (fig. 1, ~) is shallower. 
The ectocalcaneal process (s) is narrower : the groove on the outer side of that process 
is also narrower, and is defined by a ridge not developed in Didus. 'The short ridge or 
process below the posterior margin of the entocondylar cavity in Didus (fig. 10, 7) is 
more developed; it is feebly indicated in Pezophaps, and is continued into the ento- 
gastrocnemial ridge (fig. 4, g), which is not the case in Didus. Didus has not the 
entometatareel ridge (fig. 4, ¢) anterior to the entogastrocnemial ridge (ib. g), but only 
the latter, which is strongly marked and more internal in position (fig. 16, q): 
The postinternal depression (fig. 2, v) receiving the larger of the two upper inter- 
osseal canals (7) is narrower, and in Pezophaps minor deeper, than in Didus, owing to the 
more posterior position, in Pezophaps, of the entogastrocnemial ridge (7) defining that 
depression internally. The antero-superior interosseal depression (7) is deeper in Pezo- 
phaps than in Didus; but the insertional surface for the tibealis anticus (fig. 14, 7) is 
better-defined in Didus, The anterior ectometatarsal ridge (fig. 1, £) is more strongly 
marked in Pezophaps than in Didus. 
The groove leading to the lower interosseal canal is more strongly marked in Didus 
(fig. 15, p) than in Pezophaps (fig. 3, p), and indicates a more powerful “adductor 
muscle,” the tendon of which emerges at the interspace between the neck of the middle 
and outer trochlez, in its course to be inserted into the outer toe. 
The middle trochlea (111), as compared with the outer (iv) and inner (11) trochlee, is 
larger in Pezophaps (fig. 3) than in Didus (fig. 15); its relative position to the outer and 
inner trochlez, and the consequent curve which they describe transversely, I find, in the 
specimens before me, to be the same in both extinct genera. 
In order to facilitate future comparisons and the following of the above aussi plinns 
I subjoin the names of the parts and their symbols in Pl. Ill. which appeared to me 
to call for special notice in this part of the osteology of Didus and Pezophaps. 
Parts of Metatarsus. 
marked marked 
Entocondylar cavity. . . . -. @ KEctinterosseal canal. . . . . . om 
Kctocondylar cavity. . . .. . 30 Facet for “‘ tibialis-anticus” tendon. 7 
Intercondylar process . . . .. @ Antinterosseal ridges . . . . .) OO 
Intercondylar triangular tract . . d Lower interosseal or ‘“ adductor” 
Entometatarsal ridge . ... . €@ canal, anterior orifice. . . . . »p 
Entocondylar ridge . . . . . . f | Lower interosseal or “ adductor” 
Entogastrocnemial ridge . . . . g canal, posterior orifice . . . . » 
Entocondylar tuberosity . . . . Ah Adductor bridge . oe Ee 
Antinterosseal depression . . . . 7 Entocalcaneal process . . . . .) O97 
5 
t 
Ectometatarsalridge . . ... &k Kctocalcaneal process 
Entinterosseal canal. . . . . . Calcaneal canal 
