In the Scansores, the sacrum of the Parrot is short and very broad, the ilia and ischia also short and broad, as well as the ilio sacral and sacro-sciatic bones, inclosing a small foramen ; and the pubes, uniting with the ischia in two distinct places, encloses a subdivided obturator foramen. The coccyx of the Tou can is long and very flexible.
In the Passeres, the sacrum is composed of from ten to thirteen pieces ; but in the King fisher there is but eight. The coccyx is in seven to nine pieces, very flexible in the Pies and Swallow; and in the Woodpecker very strong, and supporting on its anterior aspect, near the extremity, a remarkable, round, concave disc, formed by the coalescence and spreading of several of the bones anteriorly. Its use is evidently to support the body by being ap plied to the stems of the trees to u hich it clings in the pursuit of its prey and attaching the spreading tail feathers. The ilia, ischia, and pubes are slender in the Passeres, and the obturator foramina generally incom plete.
The pelvis of the Raptores, or Birds of prey (fig-107.), is narrower, the bones more com pact and massy, and less expanded than in the foregoing orders.
The sacrum is narrow, and composed gene rally of eleven bones, which, in the Sparrow hawk, are ankylosed to the last lumbar ver tebra. The coccyx is straight, and in seven or eight piece.s, with a large and blade-like ter minal bone directed dorsally (a).
The ilia (b) are proportionally larger, and project more dorsally than in the other orders, overlapping the spine with elongated wings, concave externally ; and a strong tapering ilio sacral plate (g), which is directed much down wards, as well as backwards, to unite with the sacro-sciatic plate (e) behind the foramen, so as to cross the line of the coccygeal bones almost at a right angle. The ischia (c) are rather short, strong, and convergent posteriorly, where they terminate by a long and pointed spine (i), with a strong but narrow sacro sciatic ossification enclosing a small foramen (h). The ischio-sacral cotyloid buttresses (f) are largely developed. The ilio-ischial angle is remarkable in being reversed or turned for ward to a marked extent,-130° in the Eagle, and 145° in the Owl (see figs. 107. and 112.
11.), a peculiarity to which we have seen, as before mentioned, a tendency in the pets is of the Tiger and some Carrtivora, and which has an evident relation to the increase of leverage for the muscular power of adduction required to grasp their prey, as also has the convergent direction of the ischia just mentioned. The pubes (d) are long, and are like the ischia, less directed backwards, form ing an ilio-pubic angle of 125° in the Eagle and 140° in the Owl. They have a great inward convergence in niost Vultures and Falcons, and in the Hen Harrier and brown Eagle are closely approximated in the median line and connected by ligaments in a sort of short symphysis ; generally the ischia and pubes unite posteriorly to enclose a small obturator foramen in the Diurnal birds of prey. In some Falcons and Vultures, how ever, according to Carus, they are united in their whole extent ; while, in the Owls, this union does not.take place at all.
The Reptile pelves present some specimens which approach the Mammalian type, in the formation of a perfect pelvic girdle by inter pubic and inter-ischial symphysis. In these animals, however, the three components of the innominate bones remain separate through out life, and are connected in the acetabula by ligament only. The manner of articula tion of the ilia with the sacrum is also cha racteristic. We have seen that in Mammals this connection of the ilia takes place about the centre or at the anterior half ; and in Birds by the whole length of the alm. In Reptiles it takes place by the tip only of the upper extremity of the ilia, giving much less strength, but far greater mobility to these bones. In the Che/oniau and Saurian reptiles also, the ilia are directed Arwards and down wards instead of backwards and downwards, as in Birds and Mammals, and thus the axis of the anterior pelvic outlet is directed upwards and forwards, and the lumbar vertebrm, instead of the coccygeal, form part of the posterior pelvic wall. The pelvic bones are simple, and the sacro-sciatic notch can hardly be said to exist.