1875.] PLANTAR TENDONS IN BIRDS. 343 
tarso-phalangeal joint into three tendons, one running to the ungual 
phalanx of each of the three anteriorly directed toes. The flewvor 
longus hallucis is inserted into the ungual phalanx of the hallux, but 
it sends downwards near the middle of the tarso-metatarsus a vin- 
culum to join the tendon of the feror perforans digitorum just before 
the trifurcation of that muscle (figs. 1 and 7). 
This condition is found in the following birds which I have ex- 
amined :— 
Gallus bankiva. Baza lophotes. 
Megacephalon maleo. Syrnium aluco (vineulum very 
Fulica atra. broad). 
Musophaga violacea. Lepteptilus argala. 
Schizorhis africana. Ardea sumatrana (vinculum very 
Crotophaga sulcirostris. slender). 
Phenicopheus, sp.? —— cinerea (vinculum scarcely 
Eudynamis orientalis. exists). 
Cuculus canorus. Cancroma cochlearia. 
Nestor notabilis. Geopelia cuneata, 
Chrysotis festiva. Ibis rubra. 
ochrocephala. Platalea ajaja. 
Ara chloroptera. Eurypyga helias. 
In Ardea cinerea and in A. sumatrana, here mentioned, the 
vinculum is stated to be extremely feeble. In Botaurus stellaris this 
condition is carried a step further, the vinculum being quite wanting. 
Prof. Sundevall states that such is the case only in the Passeres and in 
Upupa ; here, however, is a slight exception to that generalization. 
Frequently the vinculum above referred to is so considerable in 
strength that it makes the flexor longus hallucis appear to fuse with 
the flexor perforans digitorum, and only to send a slip before doing 
so to the hallux. This condition is evidently but an inconsiderable 
modification upon the previously described typical arrangement 
(fig. 2, p.341). It is, however, a stepping-stone to others, which it 
assists in explaining. It is found in the following birds, which I have 
dissected (it will be noticed that they have the hallux comparatively 
insignificant) :— 
Apteryx mantelli. Cygnus nigricollis. 
Nothura maculosa. Podiceps minor. 
Chenalopex egyptiacus. Phalacrocorax carbo. 
In many of the Accipitres diurne a slight modification of this 
arrangement is observed. The flewor longus hallucis divides into two 
moieties opposite the lower end of the tarso-metatarse, one of which 
runs to the hallux. The other part is the representative ofthe vinculum 
of the above-mentioned birds ; it is peculiar, however, in that, instead 
of joining the tendon of the flexor perforans digitorum before it is 
distributed to the anterior toes, it mostly runs down to blend with the 
slip which is associated with the inner of these (digit 2) only (fig. 3). 
This condition I have observed in 
Haliaétus albicilla, Tinnunculus alaudarius. 
In Geranoattus aguia and in Polyborus brasiliensis, besides the 
