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 oz. O. This muscle has two 

 origins (a = 0'69, 5 = 0-35), arising from two parts of the 

 surface of the ischium, below and behind the origin of the 

 glutasus maximus. I. as in the Crocodile {{hid. 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. O. tuber ischii. I. into 

 the top of the tibia, by a common tendon with the gracilis. 



22. Semitendinosus. 1*93 oz. O. tuber ischii. I. by 

 means of a tendon having a double insertion : — a, into the top 

 of the fibula; Z>, 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. ; ^, 0*65 oz. : a derives its origin from the poste- 

 rior angle of the pubes ; h 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 {ibid. 

 p. 327) ; its tendon finally terminates by becoming one of the 

 heads of the plantaris. 



25. Vastus externus. 1*01 oz. 



26. Vastus internusl o no 



ofT rx > . 2"76 oz. 



27. Crm-eus J 



28. Popliteus. None. 



29. Gastrocnemius. 2*05 oz. Consists of two parts : — 

 a, outer head, 1*29 oz. ; J, inner head, 0*76 oz. : a 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 

 calcaneum into the outer and under surface of the outer tarsal 

 bone (cuboid) : h 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 

 calcaneum ; this tendon is also joined by that of the semi- 

 tendinosus. 



30. Plantaris. 0*47 oz. This muscle takes its double ori- 

 gin, as in the Crocodile {ibid. p. 328), from the tendons of the 

 rectus femoris and agitator caudse ; and it is inserted into the 

 calcaneum and into the fascial sheet that passes under it, 

 which forms the origin of the flexor brevis perforatus of the 

 second toe. 



