1869. ] MYOLOGY OF MENOBRANCHUS LATERALIS. 463 
muscular mass, and, passing forwards, is inserted into the flexor sur- 
face of the femur just below the great trochanter, in close contiguity 
both to the insertion of the adductor and to the origin of the biceps. 
The ilio-caudal (figs. 9 & 10, Il. C) is exceedingly large rela- 
tively, and thick, forming the bulk of the lateral caudal muscular 
mass below the lateral furrow. It is inserted into the whole length 
of the ilium and its annexed rib. 
Superficial muscles of dorsal (extensor) surface of right pelvic limb, and of outer 
side of posterior part of trunk and anterior part of tail. 
£.L.D, Extensor longus digitorum. Ex. O. External oblique. F.C. Femoro- 
caudal. G. Gracilis. G. Mz. Gluteus maximus. J. Iliacus. J/. C. Tlio- 
caudal. P. Peroneus. R&.F. Rector femoris. S. Sartorius. S. MW. Semi- 
membranosus. 4S. 7. Semitendinosus. ZT. A. Tibia’is anticus. 
Gracilis (figs. 8, 9, 10, 11, & 12, G). This muscle arises from 
the middle (antero-posterior) line of the ventral surface of the pelvic 
shield. It does not, however, extend forwards for nearly the whole 
length of this elongated shield, but only as far forwards as a line 
would be situated which should join the acetabula. It is inserted 
into the postero-peroneal surface of the upper half of the tibia. 
The adductor (figs. 8 & 11, A) is very much larger than in 
Menopoma, as it springs from the middle of the pelvic shield for its 
whole length, so that rather more appears superficially in front of 
the gracilis than is concealed beneath the latter. It is inserted into 
about the upper half of the flexor surface of the femur between the 
insertions of the iliacus and femoro-caudal. 
Semitendinosus (figs. 8,9, 10, & 11, 8.7). This small muscle 
takes origin from the junction of the semimembranosus with the 
gracilis, and not from bone or cartilage. Its insertion is the outside 
of the flexor digitorum, near the pes. 
