ON THE DEEP PLANTAR TENDONS, IN BIRDS. 295 
torum gives off from its inner side the flexor slip which supplies the 
hallux, the majority of the tendon descending as usual towards the 
foot. Opposite the middle of the tarso-metatarse it is joined by the Page 345. 
tendon of the flexor longus hallucis on its outer side, whereupon the : 
conjoined tendon splits into three divisions to supply the three anterior 
toes (vide fig. 5). 
The peculiar conformation in the foot of the Trogonide is associated 
with an equally abnormal arrangement of the plantar tendons, which I 
have found in Trogon puella and in Pharomacrus mocinno. In these 
birds the tendon of the flexor longus hallucis is situated, as it ought to 
Fig. 5. Fig. 6. 
Iv ut 
IV 
Il 
Momotus lessoni. Trogon puella. 
be, external to the flexor perforans digitorum ; it also crosses it super- 
- ficially, opposite about the middle of the tarso-metatarse, sending down 
a slender vinculum in the normal manner. The peculiarity is in the 
ultimate destination of the tendons, the flexor longus hallucis and the 
flexor perforans digitorwm each dividing into two near the metatarso- 
phalangeal articulation, the two portions of the former tendon running 
to the hallux and digit 2, the two of the latter to digits 3 and 4 (vide 
fig.6). This arrangement is not found in any other group of birds, as 
far as my experience goes. 
