Fig. 12. The section is taken through the hinder part of the buccal cavity at the level of the opening of the mouth into the pharynx and behind the jaws. The cuticular rod-like continuation (_le._) of the inner jaw lying in a backwardly directed pit of the buccal cavity is shewn; on the right hand side the section passes through the opening of this pit. Fig. 13. The section passes through the front part of the pharynx, and shews the opening into the latter of the median backward diverticulum of the mouth (M{1}), which receives the salivary ducts. It also shews the commencement of the ventral nerve-cords, and the backwardly projecting lobes of the brain. Fig. 14. The section passes through the anterior part of the pharynx at the level of the second commissure (_co._ 2), between the ventral nerve-trunks, and shews the mass of cells developed on this commissure, which is in contact with the epithelium of the backward continuation of the buccal cavity (M{1}). Fig. 15. Section through the point of junction of the salivary ducts with the median oral diverticulum. Fig. 16. Section behind the pharynx through the oesophagus. _b.c._ Body-cavity. C. Cutis. _c.b.c._ Central compartment of body-cavity. _c.g._ Supra-oesophageal ganglia. _c.m._ Layer of circular muscles. _co._ Commissure between ventral nerve-cords. _co._ 2. Second commissure between the ventral nerve-cords. _co{1}._ 2. Mass of cells developed on second commissure (probably sensory). _c.s.d._ Common duct for the two salivary glands. _d.l.m._ Dorsal longitudinal muscles of pharynx. _d.o._ Muscles serving to dilate the opening of the pharynx. _Ep._ Epidermis. _e.n._ Nerve passing outwards from ventral nerve-cord. H. Heart. _i.j._ Inner jaw. _j.p._ Jaw papillæ. _L._ Lips of buccal cavity. _l.b.c._ Lateral compartment of body-cavity. _le._ Rod-like cuticular continuation of inner jaw, lying in a pit of the buccal cavity. _l.m._ Bands of longitudinal muscles. M. Buccal cavity. M{1}. Median backward continuation of buccal cavity. _m.l._ Muscles of jaw lever. _m.s._ Muscular sheets passing from side walls of pharynx to dorsal body-wall. _oe._ OEsophagus. _oes.co._ OEsophageal commissures. _o.j._ Outer jaw. _ph._ Pharynx. _s.d._ Salivary duct. _s.g._ Salivary gland. _sl.d._ Reservoir of slime gland. _sy._ Sympathetic nerves running in muscles of tongue or pharynx. _sy{1}._ Origin of sympathetic nerves to pharynx. T. Tongue. _v.c._ Ventral nerve-cords. Figs. 17, 18. Two longitudinal horizontal sections through the head of _Peripatus capensis_. Fig. 17 is the most ventral. They are both taken ventral to the cerebral ganglia. In Fig. 17 dorsal tracheal pits are shewn with tracheæ passing off from them. (Zeiss a a, Hartnack's camera.) C. Cutis. _c.s.d._ Common salivary duct. _ep._ Epidermis. _i.j._ Inner jaw. M. Buccal cavity. M{1}. Median backward diverticulum of mouth. _o.j._ Outer jaw. _s.d._ Salivary ducts. T. Tongue. _t._ Teeth on tongue. _tr._ Tracheæ. _tr.p._ Tracheal pits.