halanges each.

* Such a resemblance as exists between one vertebra and another in
the rabbit, or between the humerus and the femur, is called serial
homology; the two things correspond with each other to the extent of
imperfect reduplication. "Homology" simply is commonly used to
indicate the resemblance between any two structures in different
animals, in origin and position as regards other parts. Thus the heart
of the rabbit and of the frog are homologous structures, corresponding
in position, and resembling each other much as two memory
sketches of one picture might do.

Section 84. The pelvic girdle differs from the pectoral in most land
vertebrata in being articulated with the vertebral column. This
difference does not exist in fishes. It consist in the rabbit of four
bones; the ilium (i.), the ischium (is.), the pubis (pb.), and the small
cotyloid bone-- the first two and the latter one meeting in the
acetabular fossa (ac.) in which the head of the femur works. The
pubes and ischia are fused along the mid-ventral line. Many
morphologists regard, the ilium as equivalent to, that is, strictly
corresponding in its relation, to the scapula, the pubis to the
cartilaginous substratum of the clavicle, and the ischium to the
coracoid.

Section 85. These bones will be studied at the greatest advantage
when dissected out from a boiled rabbit. Prepared and wired
skeletons, disarticulated skeletons, plates of figures, and written
descriptions are in succession more tedious and less satisfactory
ways to a real comprehension, of this matter. This chapter directs the
student's attention to the most important points in the study of the
skeleton, but it is in no way intended to mitigate the necessity of
practical work. It is a guide simply.

Section 86. The mammalian skull will be better understood after the
study of that of some lower vertebrate. We shall describe its main
features now, but their meaning will be much clearer after the lower
type is read. Our figures are of Canis. In section (Figure VI., Sheet 6),
we perceive a brain case (cranium) opening behind by a large
aperture, the foramen magnum (F.M.). In front of this is an extensive
passage, the nasal passage (E.N. to P.N.) which is divided from the
mouth by a bony floor, the palate, and which opens into the pharynx
behind at the posterior nares (P.N.) and to the exterior by the anterior
or external nares (E.N.). It is divided into right and left passages by