1870. ] MYOLOGY OF PLATYDACTYLUS JAPONICUS. 42] 
pubis, and in front to the sides of the rectus abdominis ; its fibres 
are directed from behind forward and towards the dorsal surface. 
Intercostals are the layer of muscles next internal to the last ; 
they are united behind with the internal oblique and transversalis to 
form an arch over the external and back part of the thigh; they 
occupy the spaces between all the ribs from the sides of the rectus 
and sternum to the vertebra, anteriorly they are continuous with 
the scalenus ; their fibres are directed forward and slightly towards 
the dorsal surface. 
Internal oblique and transversalis are situated between the ribs 
aud the viscera. Posteriorly they are united together and to the 
intercostals as above mentioned; dorsad they are attached to the 
angles of the ribs internally, at the place where the external oblique 
is attached externally ; ventrad they are attached to the side of the 
rectus abdominis, and, in front of that, to the end of the fourth 
sternal rib, to the xiphisternum, and to the postero-lateral edge of 
the sternum. Anteriorly they extend as far as the fourth cervical 
rib. The fibres of the internal oblique are directed obliquely for- 
wards and towards the ventral surface; those of the transversalis go 
transversely across the body. 
Quadratus lumborum arises from the anterior edge of the sacrum. 
It is attached to the sides of six lumbar and the last dorsal vertebree, 
and encloses all the lumbar ribs in a thick muscular mass, which 
terminates anteriorly at the last dorsal rib. 
Retrahentes costarum line the whole dorsal surface of the abdo- 
minal cavity in front of last muscle. They consist of muscular slips 
separable by dissection, each arising from a centrum of a vertebra, 
and passing ventrad of the rib of its own vertebra ; and that of the 
next one in front is inserted into the next but one, interdigitating 
with the transversalis and internal oblique ; the most anterior one is 
attached to the centrum of the first dorsal vertebra and to the fourth 
cervical rib, and the last to the twelfth dorsal. 
Sartorius occupies the greater part of the ventral aspect of the 
thigh. It arises from the hook-like process of the pubis in front of 
the acetabulum, also from the whole length of the ilio-pubic liga- 
ment; it has a broad muscular insertion into the lower or inner side 
of the tibia, occupying one quarter of its proximal end. 
Gracilis arises from the side of the ischial symphysis and from the 
ventral part of a tendinous intersection which connects the posterior 
point of that bone with the posterior end of the ilium, and which 
seems to represent the tuber ischii; it is inserted partly tendinous 
and partly fleshy into the tibia, beneath the last muscle. 
Transversus perinei is a small muscle in front of the cloaca, arising 
from the proximal side of the above-mentioned tendinous intersection, 
and is inserted into a cartilaginous rod attached to the posterior end 
of the ischium, and into the skin anterior to the cloaca. 
Semimembranosus arises from the tendinous intersection dorsad 
of the gracilis, and is inserted into the tibia on the inner side of the 
internal lateral ligament, and nearer the head of the bone than the 
gracilis. There are two separate muscles which, perhaps, represent 
