344 MR. A. H. GARROD ON THE DEEP [Apr. 20, 
special tendon from the hallux-muscle to the second digit, there is a 
broad thin vinculum present, asin Gallus. In the Accipitres Diurnze 
the arrangement of the tendons therefore differs in different groups— 
in Baza their distribution being quite normal, that is as in the first- 
described manner ; in Polyborus, Haliaétus, Tinnunculus, and Gera- 
noétus this condition is combined with a special extra tendon to the 
second digit, which greatly increases its power of flexion. The 
arrangement observed in the Cathartidz is in no way allied to any 
of these, and adds another important point to the many now known 
to separate them off entirely from the Accipitres vere. 
The next arrangement to be described is a very differeut one. The 
two deep flexors descend beyond the ankle-joint independently, as 
usual ; after passing which, generally about one third down the tarso- 
metatarse, they blend completely, before any slip has been given off. 
From the conjoined tendon thus formed the tendons of distribution 
spring, four in number, one to the hallux and others to each of the 
three anteriorly directed toes (fig. 4, p. 342), that to the former 
being generally separated off before any of the others. 
Among Homalogonatous birds the only group in which I have 
observed this condition is that of the Cathartidee—both Cathartes 
atratus and Sarcornamphus gryphus possessing it, aud so differing 
entirely from their supposed allies the diurnal Accipitres. Among 
Anomalogonatous birds the arrangement is very commonly found ; 
I have seen it in 
Coracias garrula, Podargus cuvieri, 
Buceros rhinoceros, Caprimulgus europeus, 
Steatornis caripensis, Cypselus alpinus. 
On looking at the plantar tendons thus arranged, without further 
dissection, the slip to the hallux from the conjoined deep flexor 
tendon seems to spring from its inner (that is, hallucial) side; whereas, 
from what has been said above, the long flexor of the hallux is situ- 
ated external to the common flexor, at the ankle-joint. 
Further, in these birds, on straining upon the distal hallux slip 
with one hand, at the same time that the distal slips to the remain- 
ing toes are held in the other, the two elements of the conjoined 
tendons tend to divide up in the direction of the ultimate fibres ; 
and in doing so the line of rupture always develops in such a way 
that it leaves the thus further-separated hallux slip still on the inner 
side in connexion with the main flexor perforans tendon. 
A natural condition, like this thus artificially produced one, is 
found in some birds closely allied to those in which the last de- 
scribed arrangement obtains. It is found in Momotus lessoni, 
Dacelo gigantea, and Merops apiaster. In them the tendons of the 
flexor longus hallucis and of the flevor perforans digitorum pass 
down beyond the ankle-joint in the typical manner, the former exter- 
nal to the latter as usual. Opposite the upper end of the tarso- 
metatarse the flewor perforans digitorum 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 
