MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 49 



in passing between the biceps and the glutens and lies "edgewise" 

 for a short distance, its distal part being covered by the biceps. It is 

 separate from the gluteus in Sarcophilus (Macalister, 1870, p. 166) and 

 Notoryctes (Thompson and Hillier, 1905, p. 310), but in other marsupials 

 is in the same plane and more or less fused with it. 



Vastus internus. Origin from the proximal three-fourths of the 

 anterior and dorsal surface of the femur, extending from the anterior 

 edge of .the great trochanter to the lesser trochanter and thence distad. 

 Insertion with the vastus externus on the inner side of the patella and 

 thence by aponeurosis to the head of the tibia. A very large muscle 

 greatly exceeding the vastus externus. 



Subcrureus. Origin on the dorsal surface of the femur just distad of 

 the vastus internus. Insertion in the tendinous fascia surrounding the 

 patella. A short flat muscle. 



Vastus externus. Origin from the anterior border of the great tro- 

 chanter of the femur. Insertion conjoined with the rectus femoris on 

 the patella. About equal in size and form to the rectus, with which it 

 forms the anterior border of the thigh. Decidedly smaller than the 

 vastus internus to which it is closely appressed but from which it is 

 distinct except for a short distance near its origin. 



Biceps femoris. Origin by a short tendon from the lateral surface of 

 the tuberosity of the ischium craniad of the inner division of the semi- 

 tendinosus and entad of the outer division or crurococcygeus. Insertion 

 by broad aponeurosis from the patella across the proximal third of the 

 leg to the outer edge of the tibia. This aponeurosis covers a large part 

 of the outer side of the leg. A large triangular muscle of great width but 

 moderate thickness. Its anterior border meets the vastus externus and 

 covers the insertion of the femorococcygeus. 



Rectus femoris. Origin from the dorso-lateral ridge of the ilium im- 

 mediately craniad of the acetabulum. Insertion with the vasti on the 

 patella. It passes between the gluteus minimus and the ileopsoas and 

 forms the inner anterior boundary of the thigh. 



Semitendinous. Origin by two heads, an outer one ("crurococcyg- 

 eus") from the fascia over the fourth caudal vertebra and an inner one 

 from the tuberosity of the ischium just caudad of the biceps. Midway 

 between the tuberosity and the flexed femur these two slips unite and 

 then divide into three parts, two passing inside the gastrocnemius and 

 one outside. The inner slips insert by aponeurosis, one with a twist on 

 the front of the tibia one-third of the distance from the tibial head and 

 the other (entad) on the same surface of the tibia halfway between 

 its fellow and the head of the tibia. The outer slip inserts on the outer 

 surface of the tibia and in the fascia of the biceps femoris. The relations 



