422 MR. A. SANDERS ON THE [June 9, 
the ligament of Winslow and the popliteal aponeurosis: the one 
arises from the tendinous intersection in common with the semi- 
membranosus, and is inserted by a long tendon into the external 
side of the head of the tibia, between it and the head of the fibula, in 
immediate contact with the joint; the other arises from ischium, in 
front of and close to the last, and is inserted by a shorter tendon 
into the interarticular cartilage of the joint. 
Semitendinosus arises, in conjunction with semimembranosus, 
from the tendinous intersection, and is inserted by a broad thin 
tendon into the head of the tibia. 
Pelvo-tibialis arises from the edge of the pubis at a point behind 
the hook-like process of that bone, to which it is attached by a strong 
aponeurosis, and passing obliquely across the thigh it reaches the 
popliteal space, where it suddenly becomes tendinous and penetrates 
the knee-joint, being inserted into the head of the tibia between it 
and the fibula, external or anterior to the attachment of the section 
of semimembranosus mentioned above. This appears to correspond 
in insertion to the muscle called ‘‘ biceps” by Mr. Mivart; but in 
this animal it is quite on the ventral aspect of the thigh; so I have 
ventured to give it a distinct name. 
Pectineus arises by a membranous expansion, attached to the an- 
terior point of the ischial symphysis and to the ischio-pubic ligament, 
and is inserted into the ventral surface of the shaft of the femur, 
occupying about the middle third. 
Rectus femoris arises by two heads :—one from the surface of the 
pubis immediately anterior to the cotyloid cavity, and from the 
capsule of the hip-joint ; and the other from a varying extent of the 
ilium, in this case from two-thirds of its length. They join together 
and form a fleshy mass covering the anterior and dorsal surtace of 
the thigh ; the whole is inserted into the tuberosity of the tibia by 
means of a tendon containing a sesamoid bone. Being unable to 
decide whether the iliac origin of the muscle represents the gluteus 
maximus or not, I have preferred to leave the text as it has been 
written. 
Biceps femoris arises from the ilium immediately behind the 
superior origin of the rectus; it is inserted into the fibula on the 
proximal side of its central point by a flat tendon, which is covered 
by the peroneus brevis. 
Coccygeus.—There are three muscles which have attachments 
corresponding to this muscle. The one which may be called superior 
arises from the extremities of the transverse processes of the five 
anterior caudal vertebree, and is inserted into the posterior extremity 
of the ilium ; it has two interdigitations with the first caudal muscle. 
Coccygeus medius arises from the sides of the six anterior caudal 
vertebrze ventrad of the transverse processes, and is inserted into the 
tendinous intersection internal and behind the semitendinosus, its 
anterior border forming a straight line from that point to the first 
caudal vertebra. In the Iguana Mr. Mivart calls this the pyrifor- 
mis; but here it has not the slightest attachment to the femur, and 
so could hardly represent that muscle. 
