382 MR. ST. G. MIVART ON THE ANATOMY OF ECHIDNA HYSTRIX. 
The pyramidalis is very largely developed, and lies immediately beneath the ten- 
dinous aponeurosis of the external oblique. It arises from the whole inner surface of 
the marsupial bone, and from its internal margin within the insertion of the external 
oblique. Its superficial fibres radiate towards the middle line of the body (those fibres 
arising from the distal part of the marsupial bone being much the longest), and are 
inserted into the linea alba from the symphysis pubis to the posterior end of the sternum; 
its deeper fibres blend with with those of the rectus. 
Rectus abdominis (Plate LII. fig. 2, n.).—This arises from the deep surface of the mar- 
supial bone, towards its external margin. It proceeds forwards, and is partly inserted 
into the posterior end of the sternum (near which point it is intimately connected with 
the external oblique) ; it then continues on, being inclined somewhat outwards, and is 
inserted into the first rib, the manubrium, and, very slightly, into the coracoid, close to 
the origin of the coraco-brachialis and biceps. 
The sacro-coccygeus arises from the ventral surfaces of the sacral and first few caudal 
vertebræ, and is inserted by strong tendons into the ventral surfaces of the caudal ver- 
tebræ, a little posterior to a point opposite the tuberosity of the ischium. 
The pubo-coccygeus forms a delicate sheet of muscular fibre, and arises from the whole 
anterior (superior) margin and inner surface of the pubis, and from the inner surface 
of the ilium. It is inserted into the ventral surface of the caudal vertebræ, just opposite 
to the tuberosity of the ischium. The portion arising from the ilium is probably the 
ilio-coccygeus, here united with the pubo-coccygeus. 
Ischio-coccygeus.—This arises from the whole superior (posterior) margin of the 
ischium, from the acetabulum to the tuberosity ; it is inserted into the transverse pro- 
cesses of the caudal vertebræ for about an inch posterior to a point opposite the tube- 
rosity of the ischium. 
Levator caudæ.—This continues, as it were, the erector spine backwards along the 
groove between the neural spines and the transverse processes of the caudal vertebra. 
Muscles of the Fore Limb. 
Pectoralis major (Plate LIT. fig. 2, »).—This is a large muscle, arising from the whole 
length of the sternum and from the greater part of the median portion of the inter 
clavicle', or episternum, also somewhat from the aponeurosis of the external oblique, but 
not at all from the clavicle or from the lateral branches of the interclavicle. Its fibres 
converge to a strong tendon, which is inserted into the greater tuberosity of the hu 
merus, where it is superficial to the insertion of a deeper layer of the panniculus car” 
nosus, while an outer layer of that muscle is superficial to it. 
I could find no muscle evidently representing a pectoralis minor; but there À 9 
small and thin muscle which arises from the anterior border of the first rib for the 
greater part of its length, and which is inserted into the coracoid immediately behind 
(or rather above) the origin of the coraco-brachialis. I am inclined, however, to TS 
* A name suggested by W. K. Parker, Esq. 
