51 
ventral extremity of the pubis and from the inter-pubic ligament : it soon becomes fleshy ; 
the carneous portion is interrupted by three broad, oblique, but distinct aponeurotic in- 
tersections (g*), and is finally inserted into the xiphoid and lateral processes of the ster- 
num and the intervening fascia. 
Transversalis abdominis.:—A layer of loose, dark-coloured cellular tissue divides the 
internal oblique from the transverse abdominal, except at its origin from the pubis, and 
for half an inch anterior to that part. 
The transversalis then proceeds to derive carneous fibres from the inner surface of the 
vertebral ribs near their lower third; they pass obliquely upwards and forwards, and 
terminate by a regular, slightly concave line midway between their origins and the ex- 
tremities of the ribs ; a strong aponeurosis passes thence to the linea alba, but becomes 
thin at the pubic region, where a mass of fat is interposed between it and the peritoneum. 
Diaphragm (Pl. V1.).—This muscle presents more of its normal mammalian character 
in this than in any other known bird, It is perforated by vessels only, in consequence 
of the non-development of the abdominal air-cells. The origin corresponding to that 
of the lesser muscle in Mammalia is by two strong and distinct, short tendinous pillars 
(aa), from the sides of the body of the last costal vertebra ; they are united by a strong 
tendon or fascia, forming the anterior boundary of the aortic passage. The tendinous 
pillars may be traced forward for some way in the central aponeurosis, expanding without 
crossing ; they are then lost in that aponeurosis, which is perforated by the gastric arte- 
ries and veins ; decussates and divides anteriorly (at }) to give passage to the gullet and 
the apex of the heart ; the aponeurosis expands over the anterior part of the thoracic 
air-cells, and becomes, at its lateral circumference, the point of attachment of muscular 
fibres arising from the inner surface of the anterior ribs, and forming apparently a con- 
tinuation of the transversalis abdominis. 
Appendico-costales (Pl. XI. h).—Origin. From the posterior edge and extremity of the 
costal processes or appendages. Jns. They run down to be inserted severally into the rib 
posterior to that to which the process affording them origin is attached. These pro- 
cesses are supported by strong triangular aponeuroses continued from their anterior and 
upper margins, severally, to the rib anterior to them. 
‘The muscles of the jaws have already been described in the account of the digestive 
organs. The following are shown in Pl. XI.: «, temporalis externus ; 8, temporalis in- 
ternus; y, biventer mawille ; the masseter has been removed, but is shown at , Pl. XIII. 
fig. 1. The internal pterygoid muscle is shown in Pl. XIV. at ¢; the external pterygoid 
at C. 
Some of the muscles of the tongue, which are described in the first part of this me- 
moir (p. 8), are delineated in Plate XIII, fig. 1. 
The strong orbicularis palpebrarum has been divided and reflected forwards at 6, Pl. XI. ; 
it is shown im situ at fig. 1, Pl. XIII. 
