On the Leg and Toe Bones of ‘ Ptychosiaguwm.” 235 
and a very marked resemblance in the structure of the claw. 
Among the Edentates the first phalanx is similarly shortened in 
certain toes of the Armadillo and the Sloth. In Oudenodon and 
Dicynodon, so far as is known, the phalanges are all well developed. 
In those toes of Cynodraco which I have recently discovered the 
phalanges are likewise all well developed. 
From the position of the nostrils in Ptychosiagum one would 
naturally conclude that it had been an aquatic form, and the 
structure of the leg and toes confirms this view. 
BHXPLANATION OF PLATE XXXII. 
= 
Lond 
Q 
ODARMNARWDHYEHSE 
. Front view of tibia of Ptychosiagum Murray. 
. Outer view of tibia and fibula of Ptychosiaguwm Murray. 
Ms Be oF Petauroides volans. 
5 cab e Echidna aculeata. 
oe Ornithorhynchus anatuvus. 
; Dader surface of fourth (? third) toe of Ptychosiagum Murray. 
. Side view 
. Upper surface of second toe of right foot of Hchidna aculeata. 
. Upper surface of fourth (? third) metatarsal of Ptychosiagum Murrayt. 
. Upper surface of third (? second) toe of Ptychosiagum Murrayt. 
. Side view of ungual phalanx of third (? second) toe of P. Murrayt. 
. Articular surface of ungual phalanx of 
ft et 
DH © 
9) ”” 
