244 MR. G. E. DOBSON ON CAPROMYS MELANURTJS. [Apr. 1, 



Adductor brevis (fig. 3, a. b) is very large, arising from the 

 symphysis pubis and ramus of the pubis and ischium as far as the 

 tuber ischii ; it forms a thick and broad muscular mass inserted along 

 nearly the whole length of the shaft of the femur in its middle 

 third under cover of the insertion of the addxictor longus, and in its 

 lower third extending to the insertion of the adductor magnus. 



Adductor magnus (fig. 3, a. m), long and narrow, arises from the 

 tuber ischii under cover of and in connexion with the deep head of the 

 biceps flexor cruris, and passes forwards, separated from this muscle 

 by the great sciatic nerve, to its insertion into the femur immediately 

 above the point of origin of the internal head of the gastrocnemius, 

 with which it is slightly connected. 



Adductor quartus is large, covering the obturator externus ; it 

 arises from the lower and part of the posterior and anterior margins 

 of the obturator foramen under cover of the adductor brevis and 

 adductor longus, and is inserted into the shaft of the femur imme- 

 diately below the lesser trochanter and between it and the insertion 

 of the adductor brevis. 



Pectineus (fig. 3, p) arises above the adductor longus from the 

 margin of the pelvis below and behind the acetabulum, and is inserted 

 into the middle third of the shaft of the femur, in front of the 

 adductor longus. 



Semi-membranosus (fig. 3, s.iii) arises from the ramus of the 

 pubis and the ischium, behind the adductor brevis, and is inserted 

 behind the internal lateral ligament. 



Semi-tendinosus (fig. 3, s.t) arises by two heads — one small, 

 from the tuber ischii immediately above the semimembranosus, and in 

 connexion with the biceps flexor cruris ; the other from the last coccy- 

 geal vertebrae and the side of the base of the tail ; the anterior part 

 of the latter unites with the posterior margin of the deep head of 

 the biceps flexor cruris, the posterior part with the deep head 

 described above arising from the tuber ischii, and is inserted below 

 the gracilis into the shaft of the tibia. 



Psoas parvus is small, arising from the first to the fourth lumbar 

 vertebrae, and inserted tendinously into the margin of the pelvis. 



Psoas magnus, much larger, arises further backwards from the 

 bodies of the third to the last lumbar vertebra, close to its fellow of 

 the opposite side ; unites with the iliacus, and is, with it, inserted 

 into the lesser trochanter. 



Obturator externus arises under cover of the adductor quartus from 

 the margin of the obturator foramen and from the obturator ligament, 

 and, forming a thick muscular tendon, is inserted into the neck of 

 the femur. 



Extensor digitorum longus arises by a tendon from the external 

 condyle of the femur, and, passing down under cover of the tibialis 

 anticus, enters the foot, and is distributed to the four outer toes. 



Tibialis anticus is very large, arising from the head of the tibia, 

 from the upper half of that bone, and from the interosseous ligament ; 

 it forms a thick tendon which curves round the side of the foot, and, 

 passing under cover of the abductor ossis metatarsi halluces, is inserted 



