The anterior lateral sulcus (Fig. 138, _r_) may be traced craniad from the origin of the ventral roots of the first cervical nerves (_s_), along the lateral border of the area elliptica (_n_), then curving mediad to the lateral border of the pyramis (_o_), and finally reaching the pons (_i_). Its position is marked by the origin of the roots of the hypoglossal nerve (_XII_). The posterior lateral sulcus (Fig. 141, _b_), marked on the spinal cord by the origin of the dorsal nerve-roots, curves laterad at the sides of the fourth ventricle (_h_) owing to the increasing width of the latter, and ends at an elevated area of oblique fibres, the =area ovalis= (_f_). The columns or funiculi bounded by the longitudinal fissures present the following peculiarities: The anterior white funiculus of the cord is replaced in the medulla by the =pyramidal tracts= (=pyramides=) (Fig. 138, _o_). The pyramidal tracts are formed by fibres which emerge from beneath the pons and pass caudad to disappear just craniad of the level of the first cervical nerve (_s_). The pyramidal tracts are bounded medially by the anterior median fissure (_p_), but laterally each is separated from the anterior lateral sulcus (_r_) over its caudal part by an elongated =area elliptica= (_n_), the human homologue of which is uncertain. It perhaps represents the =oliva=. Laterad of the cranial portion of the pyramids is an irregular area known as the =trapezium= (_l_) which abuts caudad on the area elliptica (_n_) and the area ovalis (_m_). The =area ovalis= (Fig. 138, _m_; Fig. 141, _f_) (or zonula Arnoldi) is abroad band of oblique fibres which passes from the lateral side of the area elliptica craniodorsad to disappear under the cerebellum. The posterior white funiculus was divided in the cervical region into two, the =fasciculus gracilis= (column of Goll) and the =fasciculus cuneatus= (column of Burdach). The fasciculus gracilis (Fig. 141, _c_) extends to the caudal end of the fourth ventricle (_h_) and ends there in an expansion, the =clava= (_d_), which forms the posterior boundary of the fourth ventricle. The fasciculus cuneatus (_e_) passes laterad on account of the width of the fourth ventricle and appears to end at the area ovalis (_f_), but it may be seen passing beneath the area ovalis, emerging at its cranial border and turning dorsad to enter the cerebellum. It forms the side walls of a part of the shallow fourth ventricle. The lateral funiculi are divided by longitudinal furrows into three divisions. The dorsal one of these is the =fasciculus cuneatus lateralis= or column of Rolando (Fig. 141, _g_). It accompanies the fasciculus cuneatus into the cerebellum. The entire mass formed by the fasciculus gracilis, the fasciculus cuneatus medialis, and fasciculus cuneatus lateralis is known as the =corpus restiforme=, and since its fibres pass into the cerebellum it is sometimes known as the =pedunculus cerebelli= (or crus cerebelli ad medullam).