MR. ST. G. MIVART ON THE ANATOMY OF ECHIDNA HYSTRIX. 381 
arises from the ventral surfaces of the bodies of first three dorsal vertebræ, and is inserted 
by a strong tendon into that part of the basis cranii which appears to answer to the 
styloid process; but the mutilated condition of the skull of my specimen renders this 
determination a little uncertain. 
The rectus capitis anticus minor arises from the transverse process of the axis, and is 
inserted into the base of the skull within the tendon of the muscle last described. 
Longus colli.—This muscle is very weak and small, the Echidna thus differing from 
the Ornithorhynchus', as might be expected from the difference in the development of the 
hypapophysial processes. It arises from the ventral surfaces of the first six dorsal 
vertebræ, and from the transverse processes of the cervical vertebræ as far forwards as 
the axis, and is inserted into the transverse processes of the last two or three cervical 
vertebræ and into the bodies of all the cervical vertebræ, especially into the hypapophysis 
of the atlas, by strong tendinous fibres. 
Scalenus.—There appears to be but a single scalenus muscle, which arises from the 
transverse processes of the cervical vertebræ, from the second to the seventh inclusive, 
and is inserted into the first rib. The brachial vessels and nerves pass out beneath (in 
front of) it. í 
The sterno-mastoid (Plate LII. fig. 2, s.m), a very long and narrow muscle, arises, in 
close connexion with its fellow of the opposite side, from the middle of the outer surface 
of the manubrium. It is inserted by a strong tendon into the mastoidal region of the 
skull above and in front of the insertion of the ¢rachelo-mastoid. It is an interesting 
faet that the sterno-mastoid does not arise from the anterior border of the shoulder- 
girdle, but, as it were, follows its own normal point of attachment (the manubrium) 
backwards behind the episternum. Meckel?’ represents it, however, as arising from the 
clavicle in the Ornithorhynchus. 
The sterno-thyroid and sterno-hyoid arise deeply within the thorax, namely, from the 
internal surface of the true sternum as far back as the attachment of the fifth rib. The 
sterno-hyoid passes upwards beneath the larynx, and appears to be continued on into the 
hypoglossus, as in the Ornithorhynchus’. 
The external oblique arises by digitations from all the ribs except the first, and from 
the ilium. It is inserted by a strong tendon into the anterior (upper) border of the sym- 
physis pubis, into the internal and external margins of the marsupial bone, and has 
another strong tendinous insertion into the margin of the pubis just external to the base 
of the marsupial bone. The tendinous fibres of this muscle decussate with those of its 
fellow on the opposite side. 
_ The internal oblique is exceedingly thin and delicate ; 
Mserted into the expanded cartilages of the false ribs. 
Transversalis.— This muscle, as in the Ornithorhynchus 4 is more developed than the 
Preceding. It arises from the ilium, the transverse processes of the lumbar vertebree, 
ànd from within the expanded cartilages of the ribs. Its aponeurosis blends with that 
its fellow of the opposite side above (i. e. behind) the rectus. 
it arises from the ilium, and is 
! Meckel, loc. cit. p. 26. ? See loc. cit. tab. v. no. 8. : 
* Owen, loc. cit. p. 381. 4 Meckel, loc. cit. p. 25, and Owen, loc. crt. p. 381. 
VOL. xxv. oH 
