ON THE DEEP PLANTAR TENDONS IN BIRDS. 289 
is thee end Pistalon. 
The skull is schizorhinal. 
The angle of the mandible is 
produced and recurved. 
The pectoralis major muscle is 
simple, not being separable into 
distinct layers. 
The accessory femoro-caudal 
muscle is well developed. | 
The semitendinosus muscle is 
muscular throughout. 
A small muscular belly is sent 
from the biceps cubiti to the 
In Oiconia and Tantalus. 
The skull is holorhinal. 
The angle of the mandible is 
truncated. 
The pectoralis major muscle is 
in two layers, a superficial and a 
deep, easily separable one from 
the other. 
The accessory femoro-caudal 
muscle is absent. 
The semitendinosus muscle is 
tendinons for its distal half. 
No slip leaves the biceps cubiti 
muscle to join the tensor patagii 
tendon of the tensor patagii longus longus. 
muscle. 
46. ON THE DISPOSITION OF THE DEEP PLANTAR 
TENDONS IN DIFFERENT BIRDS.* 
~ ‘Te arrangement of the tendons in the palm of the hand and the Page 339, 
sole of the foot among the Mammalia is a subject of great intrieacy, as 
may be inferred from the comparison of the dissections of different Page 340. 
animals whose anatomy has been sufficiently investigated. Among 
birds peculiarities in the disposition of the plantar tendons has already 
attracted the attention of Professor C. J. Sundevall, who, as is well 
known, divides the Passeres off from all other orders, and includes 
Upupa with them, because in them, and in them only, the tendon of 
the flezor longus hallucis musele is quite independent of that of the 
flexor perforans digitorum ; whilst in other birds the former joins,the 
latter, so preventing the two from being quite independent in their 
2 action. Ali other descriptions which I have seen of special dissections 
> have been confirmatory of this view; and my own observations, with 
but a slight exception in the case of Botaurus, to be mentioned below, 
support Professor Sundevall’s separation off of the Passeres together 
with Upupa on this particular character. My dissections, however, 
have shown me that there is still more to be learnt from the plantar 
tendons, and that the large mass of birds which all agree in that the 
two above-mentioned deep flexors blend together, present among 
* “ Proceedings of the Zoological Society,” 1875, pp. 339-48. Read, April 20, 
1875, 
U 
he 
