SKELETON OF PHORORHACOS INFLATUS. 83 
In Grus the wetatarsus differs in the complication of the hypotarsus and the position 
of the inner (2nd) trochlea, which is high up and much deflected backward. 
In Psophia there is a close canal in the hypotarsus, otherwise the bone is much 
like the fossil. 
In Cariama the metatarsus in most respects closely resembles that of Phororhacos, 
but it is proportionately more slender, and at its distal end the lateral trochlee 
(particularly the inner 2nd) are less reduced. The metatarsus of Ciconia is similar in 
many points, but at the proximal end the hypotarsus is longer, its crests much more 
prominent, and it is situated further below the glenoid surfaces than is the case in 
Phororhacos. At the distal end the chief difference is that the lateral trochlez are larger 
in proportion to the median one. 
In most Accipitrine birds the metatarsus is widely different, both in the form of the 
hypotarsus and the deep excavation of the hinder surface of the shaft for the various 
muscles of the toes and the arrangement of the trochlee. Serpentarius, however, has 
undergone such modification in correlation with its terrestrial habits that it approaches 
Phororhacos very much more closely than do the rest of the group: this is chiefly the 
result of the elongation of the shaft and the alterations in the form of the talon and in 
the arrangement of the trochlee. Nevertheless, there are several points, such as the 
almost complete absence of an intercondylar tuberosity, in which it differs widely 
from the fossil. 
The dimensions of the metatarsus are :— manne 
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otmmiddletrochlea, Stata yeah st) caso oe ce hire senor Lo: 
2? 
Only one of the phalanges of the hind foot belonging to the skeleton above described 
is preserved, but there is a nearly complete left pes of another individual of the same 
species. In thisit is seen that the hallux was well developed and terminated ina strong 
hooked claw: the metatarsal articulates with the tarso-metatarsus by a simple knob, 
and terminates distally in a trochlear surface with a deep pit for ligament on its outer 
side. The total length of this toe is about 53 mm. In the second digit there are, as 
usual, three phalanges, the terminal (3rd) one being sharp-pointed and slightly hooked; the 
remaining two, though shorter than the phalanges of the middle digit, are nearly as stout. 
The lengths of the phalanges are: Ist, 31 mm. ; 2nd, 32 mm.; 3rd (ungual), 56 mm.; the 
total length of the toe isabout 93 mm. The middle toe consists of four phalanges, the 
first of which is nearly as long as the two proximal phalanges of the second digit together ; 
both it and the two succeeding digits are somewhat compressed from above downward. 
The ungual phalangeal is a powerful hooked claw. The lengths of the phalanges are: 
Ist, 55 mm.; 2nd, 38 mm.; 3rd, 27 mm.; 4th (ungual), 44 mm. 
Of the inner toe only the ungual and one of the other phalanges is preserved; the 
length of the former is about 27 mm. 
