52 THE SKELETON OF THE HORSE 
and presents a deep central depression and two shallower lateral ones which adapt 
it to the surface of the cerebellum. 
The parietal border (Margo parietalis) is united by suture with the parietal 
and interparietal. The mastoid border (Margo mastoideus) joins the petro- 
mastoid part of the temporal bone. The basilar part is connected by cartilage (in 
the young subject) with the body of the sphenoid. The condyles articulate with 
the atlas. 
Development.—The occipital bone ossifies in cartilage from four centers, and 
consists at birth of four pieces as described above. The lateral parts unite with the 
Fic. 30.—CraNIUM OF NEW-BORN Foat; Posterior View. 
A, B, C, Squamous, lateral, and basilar parts sf occipital bone; D, interparietat bone; EF, parietal bone; F, squa- 
mous temporal bone; G, petro-mastoid part of temporal bone; 1, external oecipital protuberance; 2, 2, depressfons in 
which complexus tendons are attached; 3, sutural (preinterparietal?) bone; 4, supraorbital process; 5, zygomatic 
process of temporal bone; 6, postglenoid process; 7, posterior process of squamous temporal bone; 8, mastoid process; 
9, paramastoid process; 10, occipital condyle; 11, arrow in foramen magnum. 
basilar part at three to four months, and with the squama in the second year, when 
the bone is consolidated. 
The parieto-occipital suture and the spheno-oecipital synchondrosis are ob- 
literated about the fifth year usually. The oecipito-mastoid suture partially ossifies 
in old subjects. 
THE SPHENOID BONE 
The sphenoid bone (Qs sphenoidale) is situated in the base of the cranium, its 
central part lying in front of the basilar part of the occipital. It consists of the 
body, two pairs of wings, and two pterygoid processes. 
The body (Corpus) is situated medially; it is cylindrical, but flattened dorso- 
ventrally, and wider in front than behind. Its ventral surface (Facies externa) is 
convex in the transverse direction, and its anterior part is concealed to a large extent 
by the vomer and pterygoid bones. The cerebral surface (Iacies cerebralis) 
presents the following features: (1) In front there is a raised, flattened part (Jugum 
sphenoidale) which is partially subdivided by a median elevation into two slightly 
concave lateral areas; this part has a posterior, thin, free margin (Limbus sphe- 
