In the great American Ant-eater, both the ilia and ischia abut closely on the sacral trans verse processes, presenting a faint suture at the line of junction. The pelvis is proportion ately smaller and lighter, and the processes and spines much less marked than in the Cape Ant eater. The lumbo-iliac angle in the Ant-eaters is 110°, the ilio-ischial I 40° ; and the ilio*pubic is reversed, and about 155°.
The Manis possess pelves of the same ge neral heavy appearance as the American Ant eater. The ilia and ischia are closely approxi mated, but not ankylosed to the sacrum. The symphysis pubis is short and not joined by the ischia, and the pelvic openings comparatively small.
In the foregoing Sloths and Edentata, and in some of the Rodents, we have remarked the tendency of the anterior symphysis to become shorter and more imperfect by the absence of median union of the ischia, and that this is accompanied by a corresponding increase of the bond of union between the sacrum and ilio-ischian elements of the pelvis, by, a closer approximation or ossification of their uniting ligaments, to give greater firmness to the pelvis as its anterior connection fails.
In the Insectivora and Bat tribe, this separa tion of the innominate bones is increased, and the pubes also fail altogether, in many in stances, to meet in the median line. By the classification of animals according to their pelvci development, which is here adopted„ these tribes are placed much lower than their general osteology allows, in the general classi fication commonly given by authors, and are allied more closely to the Bird type in their pelvic formation.
Of the Insectivora, the Hedgehog presents the least pelvic departure from the common mammalian type. The sacrum is narrow and triangular, and composed offour vertebrm, three of which articulate with the ilia. The ilia are thin and elongated, and placed on the spine at an angle of 130°. The ischia are slender, projecting above the level of the sacrum, but not touching it ; and the rami are long and slender, and enclose with the pubes large obturator foramina. The pubes are long, slender, and obliquely directed, making an ilio-pubic angle of about 150°. The-symphysis is very short, and the pelvic outlets large, with the long diameters antero-posterior.
In the Tupaia, one sacral vertebra only, out of three, unites with the ilia, and there is a good sized symphysis pubis, as is also seen in the Tenrecs. In the genus Desman two sacral ver tebrm articulate with the ilia and one with the ischia ; and the pubes are very obliquely placed on the ilia, and, according to Blainville, are. placed, anteriorly, rather in contiguity than in symphysis, giving to the pelvis very much of the appearance of that of the Ostrich. In the illacroscelides there is a short and rudi mentary pubic symphysis.
The Mole (Talpa) and the Shrews (Sorcx) are remarkable for a very narrow sacrum, com posed, according to Blainville, of four ver tebrm, but, according to Cuvier, of seven in the Mole and three in the Shrews. In the
Mole the ilia are solidly ankylosed to nearly the whole length of the sacrum. In the Shrews the two first only of the sacral pieces are united with the ilia. The spines in both are coalesced into a prominent sacral crest. Caudal pieces numerous.
The ilia are cylindrical, much approximated, and parallel to the spinal column. The ischia are much elongated, and elevated posteriorly above the sacral vertehrm. The pubes are very short and slender, and though they unite with the short ischial rami to enclose a small obtu rator foramen, do not meet in a symphysis, but present an anterior interval, said to be wider in the female than the male, and causing the whole pelvis to assume very much a bird-like appearance. The pelvic cavity and outlets are so strait that the sexual and urinary organs and rectum pass altogether in front of it.
In the Bats (Cheiroptera) the sacrum (fig. 103, e), is very narrow, compressed posteriorly into a straight continuous bone, with no lateral foramina, and composed of three to four ver tebrm, which are joined by ankylosis to three or four upper coccygeal vertebrm, or to more in the tailed species. There are six to twelve caudal bones, sometinies absent, as in Pteropus and Vampire.
The ilia (a,) are narrow and subcylindrical, with a thick anterior spine, placed parallel to the vertebral column, and ankylosed to the anterior sacral vertebrm. The ischia (c) are in the same right line with the ilia, and are ankylosed at the tuberosities with the last sacral vertebrw, and, as seen especially in the Ternate Bat, given in the above figure, pre senting an appearance as if ankylosed to each other in one mass, from the extreme narrow ness of the sacrum at that part, inclosing a small sacro-sciatic foramen. The pubes (b) are thick, short, and very oblique, joining with the short ischial rami at d, to form an elon gated obturator foramen (f). The ilio-pectineal spine (h) is very prominent, and recurved almost like a marsupial bone. This is especially seen in the Vespertilio spectrum, in which it is considered by Wagner as the first indication of a marsupial bone. The pubic symphysis is totally wanting generally in the Bat tribe, leaving a large interval (d, d'); but, accord ing to Pallas and Schreger, the males of some species possess a symphysis, which is wanting in the female, a peculiarity curiously illustra tive of the influence of sex on the pelvis. In a specimen in the Hunterian Museum the symphysis, or a close approximation of the bones, is certainly present, though very short. The cotyloid cavities in the bats are closely approximated, and are directed backwards as well as outwards, causing the retroversion of the feet seen in these animals. The pelvic cavity and outlets are much more capacious than in the Mole and Shrew.