MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 57 



others but this could not be determined. It represents, at least in part, 

 the flexor digitorum communis brevis, which is similarly but more highly 

 developed in Didelphis. 



Adductors. All the adductors except the medius are present. Those 

 of the outer digits arise in the membranous fascia just proximad of the 

 metatarsals. The indicts goes to the medial or fibular side of the first 

 joint of the index digit, the annularis goes to the tibial side of the same 

 joint of the fourth digit, and the minimi digiti to the tibial side of the 

 fifth digit. In one specimen the indicis and annularis were joined prox- 

 imally for at least half their length, the minimi digiti being distinct from 

 the base of the metatarsus. They are rather flat, wide, and quite delicate, 

 but have small central tendons. 



Hie adductor hallucis lies along the lateral surface of the first meta- 

 tarsal between the abductor hallucis and the short flexors and is the 

 largest of the intrinsic hallucal muscles. It is not connected with the 

 other adductors but has independent origin from the scaphoid by a 

 ^relatively stout tendon which passes along the grooved surface of the 

 ectocuneiform becoming fleshy at the base of the metatarsal. It inserts 

 with the abductor on the tibial side of the distal extremity of the first 

 metatarsal. The adductor hallucis is thus quite different from that of 

 Didelphis and somewhat similar to that of Phascologale as described by 

 Cunningham (1882, p. 55), but is even more independent, its origin being 

 completely separate from that of the other adductors. 



Abductors. These consist of an abductor hallucis, abductor minimi 

 digiti in two divisions, abductor ossis metatarsi minimi digiti, and four 

 interosseus muscles. 



The abductor hallucis is rather poorly developed and muscular only 

 in its short fan-shaped proximal part. It arises in the fascia surrounding 

 the small sesamoid laterad of the base of the first metatarsal and sends 

 a thin tendon to insert on the radial side of the distal extremity of the 

 same phalanx. 



The abductor ossis metatarsi minimi digiti is well developed arising on 

 the os calcis and running laterad of the plantar tendon to insert on the 

 tuberosity of the fifth metatarsal. 



The abductor minimi digiti is in two divisions. The first arises as a 

 thin fan-shaped fleshy muscle from the os calcis ectad of the foregoing 

 and soon becoming a slender tendon continues by a marginal course to 

 its insertion on the radial side of the distal extremity of the fifth meta- 

 carpal. The second division, which is muscular throughout, arises from 

 the sesamoid at the inner (medial) base of the fifth metacarpal and in- 

 serts on the outer (radial) sesamoid at the distal extremity of the fifth 

 metacarpal, passing between the divided short flexors. The external 



