The =malleus= has a somewhat rounded head (fig. 100, B, 1) which articulates with the incus, while the other end of the bone is drawn out into a long process, the =manubrium=, which lies in relation to the tympanic membrane. The head is also more or less connected by a thin plate of bone, the =lamella=, to another outgrowth, the =processus longus=. The =incus= (fig. 100, B, 3) is somewhat anvil-shaped, and is drawn out into a process which is connected with the =lenticular=, a nodule of bone interposed between the incus and the stapes, with which it early becomes united. The =stapes= (fig. 100, B, 2) is stirrup-shaped, consisting of a basal portion from which arise two =crura=, which meet and enclose a space, the =canal=. The _squamosal_ (fig. 73, 7) is a large bone occupying much of the side wall of the cranial cavity, and articulating above with the parietal, and behind with the supra-occipital, while in front it overlaps the frontal and alisphenoid. But though it occupies so large a space on the outer wall, it forms very little of the internal wall of the skull, but is really like a bony plate attached to the outer surface of the cranial wall. The squamosal is drawn out into a strong forwardly-directed =zygomatic process= which meets the jugal or malar. The ventral side of the zygomatic process is hollowed out, forming the =glenoid fossa= (fig. 75, 8), a smooth laterally elongated surface with which the lower jaw articulates, while the hinder edge of the glenoid fossa is drawn out into a rounded =postglenoid process= (fig. 75, 23). The articulation is such as to allow but little lateral play of the lower jaw. (2) =Bones in relation to the Optic capsules.= The only bone developed in relation to the optic capsule on each side is the _lachrymal_. This is a small membrane bone lying between the frontal and palatine behind, and the maxillae and jugal in front. It is perforated by a prominent =lachrymal foramen= (fig. 73, 13) which opens within the orbit. (3) =Bones in relation to the Olfactory capsules.= In connection with the =olfactory capsules=, five pairs of bones are developed, two pairs being membrane bones, and three pairs cartilage bones. Of membrane bones, the _nasals_ (fig. 73, 4) are a pair of long narrow bones, lying closely side by side, and forming the main part of the roof of the olfactory chamber. Their posterior ends overlap the frontals, and the outer margin of each is in contact with the nasal process of the frontal, and with the maxillae and premaxillae.