Page 348. 
298 ON THE DEEP PILANTAR TENDONS IN BIRDS. 
these tendons in birds which do not possess the hallux, or in which 
there is no long flexor tendon to that digit when it is present. In all 
these cases both the flezor longus hallucis and the flexor perforans digi- 
torum muscles are present and well developed, only they blend com- 
pletely opposite the upper part of the tarso-metatarse to form a single 
common tendon to be distributed, on its splitting up, to the anterior 
toes—to the two of Struthio, the three of Rhea, Otis, &c. Dr. Alix* 
has described how that, in the common Swan (Cygnus olor), there is 
no long flexor tendon to the small hallux. I have not examined that 
species; but there is undoubtedly a small one in OC. nigricollis, C. atra- 
tus, and in all the other Anserine birds I have examined, as above 
mentioned. However I have found this tendon to the hallux wanting 
in 
Parra africana, Pygosceles papua, 
Chauna derbiana, Podiceps minor. 
Professor C. Sundevall has shownt that in the Passeres and in 
Upupa epops the tendons of the flexor longus hallucis and the flexor 
perforans digitorum are quite free from one another, not being united 
by any vinculum. In all the Passeres which I have examined my 
observations agree with these generalizations. However, the same 
condition maintains in Botawrus stellaris and almost in Ardea cinerea, 
where the vinculum is scarcely more than a single fibre (vide fig. 9). 
DESCRIPTION OF THE FIGURES. 
In all the figures the numbering refers to the digits I, II, III, IV, representing 
the hallux, second, third, and fourth digits respectively. In all, the deep plantar 
tendons are alone represented, and these from their plantar aspect, the hallucial 
tendon being the outer of the two at the heel-joint. 
Fig. 1. Left foot of Gallus bankiva; V, vinculum running downwards from the 
outer hallucial tendon to the inner digital common tendon. 
. Right foot of Apteryx mantelli. 
. Right foot of Zinnunculus alaudarius. 
. Right foot of Buceros rhinoceros. 
Right foot of Momotus lessoni. 
Arrangement of the tendons in the left foot of Trogon puella. 
. Right foot of Crotophaga sulcirostris. 
. Right foot of Megalema asiatica. 
. Right foot of a Passerine bird. 
CONA KE ww 
* < Rssai sur l’appareil locomoteur des Oiseux.” Paris, 1874, p. 464. 
+ “ Methodi naturalis avium disponendarum tentamen” (Stockholm, 1872), and 
elsewhere. 
