482 DR. R. W. SHUFELDT ON [Noyv. 16, 
through the annular ligament in the sole of the foot, it proceeds to 
the underside of the second toe, beneath the second phalanx of 
which it expands to form a tubular sheath for the passage of the 
deep flexor, while at the same time it becomes attached to the side 
of this joint of the toe in question. 
The carneous portion of this muscle in the leg is to the outer side 
of the loop for the biceps flewor cruris, and, owing to the fact that 
it varies in form and size in different birds, it is as well to bear this 
in mind. 
The flexor perforatus medius secundus pedis (Plate XLIV. fig. 2, 
F.p,), a8 in all of the birds I have examined, is one of the best 
developed perforated tendons at the back of the leg. Its fascia of 
origin merges with the enveloping fascia about the knee-joint, while it 
also arises by a strong tendon, common to it and the flewor perforatus 
indicis secundus pedis, from the external aspect of the outer condyle 
of the femur. 
Finally, it is attached more or less by carneous fibres down the 
shafts of the leg-bones to a point below their middle, or rather the 
middle of the leg. Below this the muscle terminates in a strong 
tendon, which, taking an oblique course through the tibial cartilage, 
passes as usual over the ankle-joint, through the hypotarsus, and 
down the back of the tarso-metatarsus. 
In the foot it perforates the more superficial flexor of the basal 
phalanx of the outermost of the two anterior toes, then the turn 
bifureates over the prebasal joint to allow the deep flexor to pass 
through, these bifurcations becoming the insertions of this muscle, 
and they are attached to the sides of the shaft of the second joint of 
the toe alluded to, or the external one of the two in front. 
The flewor perforatus annularis primus pedis (Plate XLIV. fig. 2, 
J-p.@) in this bird seems to have acquired a more central position 
on the back of the leg than in many others that I have dissected, 
and, moreover, its tendon, as will be seen from the figure, is quite 
superficial. 
It arises from between the condyles of the femur by a slight 
semitendinous slip, and from the side of the flexor longus hallucis. 
The muscle itself is somewhat of a fusiform outline and rather flat ; 
it lies to the inner side of the loop for the biceps. About one third 
the way down the back of the leg it terminates in a small though 
very long tendon, which, passing quite superficially through the tibial 
cartilage and over the ankle-joint and hypotarsus, runs in common with 
the other flexors down the back of the tarso-metatarsus, turns to the 
rear in the sole of the foot to become inserted on the underside of 
the distal end of the basal phalanx of the reversed digit. In the 
specimen before me this insertion is to the outer side of the deep 
flexor, and the tendon is not slit for its passage. Nothing could be 
more engaging than the examination of these reversed tendons in 
the sole of the foot of this Ground-Cuckoo, for the greatest nicety 
in accommodation has been accomplished as they have gradually 
come to assume their present position. No doubt some of the 
departures observed from the more common arrangement of them 
are due to the reversion of the digit in question. 
Strong, fibrous bands are so disposed in this plantar region as to 
