1 84 



ANATOMY OF CERTAIN MEGAPODES. 



The extensor brevis digitorum of Owen is present in 

 these birds underlying the last-named muscle. It runs 

 along the sulcus in front of the tarso-metatarsus, and is 

 attached to that bone for the main part of its extent. 

 Just vmderneath the point where the extensor communis 

 digitorum first bifurcates, the present muscle is con- 

 verted into a tendinous expansion, which is hardly dif- 

 ferentiated into tendons, but of which separate parts are 

 inserted into the bases of the proximal phalanges of 

 digits ii., iii., and iv. From the side of the body of the 

 muscle, and about half-way down the tarso-metatarsus, 

 a small portion takes its origin, which passes to the 

 hallux, and is inserted into the base of the movable 

 metatarsus of that digit. 



M. abductor digiti iv. is a small muscle rising exter- 

 nally to the origin of m. perforatus hallucis (vide infra) 

 at the proximal end of the tarsus. It passes down the 

 postero-internal aspect of the bone, being attached to it 

 for some considerable part of its extent. About two- 

 thirds down this bone it develops a tendon, which passes 

 externally to the joint between the foot and the meta- 

 tarsus, to be inserted into the outer side of the base of 

 the proximal phalanx of the fourth digit. 



There is a strong vinculum joining the deep flexor of 

 the foot with the flexor longus hallucis, as found by 

 Garrod to be the case in the Gallinae in general. In 

 addition, there is another, not nearly so evident a vin- 

 clum, joining M. flexor perforatus digiti iii. to J\I. per- 

 foratus et perforans digiti iii. 



This latter vinculum occurs just behind the joint 

 between the metatarsus and the pes. It merely joins 

 together the two tendons in that position. 



M. perforatus hallucis is present, rising by two fleshy 

 heads, the larger from the hollow lying on the inner 

 side of the hypotarsus, the lesser from a similar but 

 smaller concavity on the outer side. In this position, 

 the tendon of the deep flexor overlies it, and passes 

 down in a grove between the partially distinct bellies of 

 the muscle. The lesser head develops a tendon much 

 in advance of the larger, the two running then side by 

 side until they fuse. The compound tendon is attached 



