Anatomy of the Alligator. — 285 
spine of the ilium, near the articulation: of the marsupial bone. 
I into the fascia of the inner side of the thigh, near its 
middle. 
19. Biceps femoris. 1°04 0z. O. This muscle has two 
origins (a=0°69, 6=0°35), arising from two parts of the 
surface of the ischium, below and behind the origin of the 
gluteus maximus. I. as in the Crocodile (eb¢d. p. 327), ex- 
cept that it is partly inserted into the head of the outer gas- 
trocnemius as well as into the peroneus longus. 
20. Bicipiti accessorius. None. 
21. Semimembranosus. 1°52 oz. OQ. tuber ischii. I. into 
‘the top of the tibia, by a common tendon with the gracilis. 
22. Semitendinosus. 1°93 oz. QO. tuber ischii. I. by 
means of a tendon having a double insertion :—a, into the top 
of the fibula; 5, into the outer tarsal bone (cuboid) with tendon 
of the gastrocnemius. : 
23. Gracilis. 0°89 oz. This muscle consists of two parts : 
—a, 0°24 oz.; b,0°65 0oz.: a derives its origin from the poste- 
rior angle of the pubes; 6 arises from the anterior prominence 
of the pubes, close to the acetabulum and to the articulation of 
the marsupial bone with the pubes. | 
24. Rectus femoris. 0°77 oz. The origin and course of 
this remarkable muscle are the same as in the Crocodile (cid. 
P: 327) ; its tendon finally terminates by becoming one of the 
eads of the plantaris. 
25. Vastus externus. 1°01 oz: 
‘ 26. Vastus > ada 276 
27. Crureus : 
28. Popliteus. None. . . 
29. Gastrocnemius. 2°05 oz. Consists of two parts :— 
a, outer head, 1:29 oz.; 5, imner head, 0°76 oz.: @ derives its 
origin, as in the Crocodile, from the tendon of the great ex- 
tensor femoris caudalis (Ann. Nat. Hist. ser. 3. vol. xvi. p.328), 
and is inserted by a tendon passing in a groove under the 
caleaneum into the outer and under surface of the outer tarsal 
bone (cuboid): 4 derives its origin from the inner condyle of 
the femur and from the top of the tibia; the tendon of the inner 
head joins that of the outer head before it passes under the 
ealeaneum ; this tendon is also joined by that of the semi- 
tendinosus. 
' 30. Plantaris. 0°47 0z. This muscle takes its double ori- 
gin, as in the Crocodile (zb¢d. p. 328), from the tendons of the 
rectus femoris and agitator caude; and it is inserted into the 
ealcaneum and into the fascial sheet that passes under it, 
which forms the origin of the flexor brevis perforatus of the 
second toe. | 
