24 A Review of the Muscles used, kc. 
two thirds down the tarso-metatarse. About opposite the 
middle of that bone the flexor longus hallucis sends a vin- 
culum downwards as in the Fowl, to join the tendon of the 
flexor perforans digitorum. Just above the metatarso-phal- 
angeal articulation the tendons become arranged for dis- 
tribution ina most uncommon manner. The tendon of 
the flexor perforans digitorum does not split up, but runs 
to one digit only, namely, the third toe, which is the outer 
of the two that are directed forward. It is covered super- 
ficially by the flexor perforans digitorum, just as that 
latter muscle is splitting up to be distributed to the hallux 
as well as to digits 2and 4. In these birds we have, there- 
fore, the flexor longus hallucis arising from the lower sur- 
face of the femur only, running through the ankle at the 
outer side of the other deep tendon, and sending a vinculum 
downwards—all of which are special characters of that 
muscle only, it being distributed to three toes, whilst the 
flexor perforans digitorum only supplies one.” 
In figure 13 the arrangement in the Apteryx is well 
shown, where the vinculum is so large as compared with 
this band in the Fowl, that it almost appears upon sight 
that the two flexor tendons are fused into one common one, 
at the point of union. 
A close study of this arrangement, however, will throw 
much light upon the variations as they are to be found in 
the less typical birds in this respect. 
