390 MR. ST. G. MIVART ON THE ANATOMY OF ECHIDNA HYSTRIX. 
large ilio-pectineal eminence, immediately behind the origin of the sartorius. It is thus 
very similar to its homologue in the Ornithorhynchus x 
The psoas magnus is a small muscle, and arises from the three lumbar vertebræ and, in 
a slight degree, from the first sacral vertebra. It becomes intimately blended with the 
iliacus, with which it has, of course, a common insertion into the lesser trochanter. 
The lumbo-saeral nerve, which appears to become the main constituent of the sciatie, 
passes down through this muscle, or between it and the next described. 
The iliacus (Plate LIII. fig. 1, 1) arises from the whole ventral surface of the ilium, 
and, becoming inseparably united with the last, is inserted into the lesser trochanter and 
its enormous ridge-like prolongation, between the insertion of the pectineus and that of 
the vastus internus. 
Quadratus lumborum.—This is a rather small muscle; it arises from the ventral 
surfaces and posterior margins of the last two ribs, and also from the sides of the bodies 
and the transverse processes of the three lumbar vertebræ. It is inserted, by strong 
tendinous fibres, into the anterior margin of the ilium. `’ 
I could find no tensor vaginæ femoris; nor does Meckel speak of its existence in the 
Ornithorhynchus. 
‘The sartorius (Plate LIII. fig. 1, s) is a long and not very broad muscle, which arises 
by à narrow tendon from the ilio-pectineal eminence, and is broadly inserted into the 
tibia, in front of the internal lateral ligament. 
The gracilis (Plate LIII. fig. 1, 6) is exceedingly broad at its origin, which is the outer 
surface of the base of the marsupial bone and the whole symphysis pubis. It is inserted 
by a strong tendon into the back of the tibia, almost on its peroneal side and below the 
insertion of the semitendinosus. 
This muscle and the preceding one much resemble their homologues in the Orni- 
thorhynchus*. 
Semimembranosus (Plate LIII. fig. 1, s.w).—This muscle arises from the tuberosity 
of the ischium (being partly covered at its origin by the semitendinosus), and is inserted 
by a strong and very thick tendon into the inner side of the head of the tibia beneath 
(i. e. covered over by) the internal lateral ligament. Its insertion is situated only very 
slightly below that of the sartorius, but considerably above that of the semitendinosus. 
The semitendinosus (Plate LITI. fig. 1, s.r) has a tendinous origin from the tuberosity 
the ischium, in close connexion with, and immediately superficial to, the origin of the 
semimembranosus. It is inserted into the posterior surface of the tibia by a rather 
small tendon, within and reaching very slightly above the insertion of the gracilis, and 
rather on the tibial side of that insertion. 
The biceps (Plate LIII. figs. 1, 2 & 3, B) arises from the tuberosity of the jschium 
superficial to, and closely united with, the origin of the semitendinosus. Spreading ont | 
greatly, it is inserted into the fascia of the front of the leg, from the patella to the ankle 
l Pectineus (Plate LIII. fig. 1, P).—This muscle is very narrow at its origin, but woe 
siderably expanded at its insertion. It arises, immediately beneath the origin of the 
sartorius, by a tendon, from the ilio-pectineal eminence, and is inserted into the limes — 
* Meckel, loc. cit. p. 28; Owen, loc. cit. p. 381. * Meckel, Joe. eit. p. 29, and tab. v. 34 & 9 
