structure of the mouth-parts in the Body-louse 211 
the walls of which it continues backwards as two divergent cornua 
(Figs. 4 and 5, rcbp., lebp.). These cornua are the fultwrae of Ender- 
lein, the plate itself being his ‘ wntere Lamelle des Pharynx’ (1904, 
p. 125, Fig. 2). To the ends of the cornua are attached three 
pairs of muscles, which have been described by Pawlowsky. The 
dorsal protractors (lateral protractors of Pawlowsky) of the right 
and left side (Figs. 4, 5, rdp., ldp., Plate VII, Fig. 1, rdp.) run 
forward from the corresponding cornua to be inserted into the 
bp. 
div. dp. 
vp. 
Fig. 3. Transverse section through buccal cavity at its function with the 
piercer diverticulum. Diagrammatic. 
dorsal wall of the head above the mouth; the ventral protractors 
(same Figs., rup., lup.) run from the underside of the cornua to 
the ventral wall of the head below the mouth; while the third 
pair, the right and left retractors of the buccal cavity (Plate VII, 
app. es 
Fig. 4. Transverse section just posterior to Fig. 3. Diagrammatic. 
Fig. 1, rrbc.) run from the cornua backwards, upwards, and out- 
wards, to be inserted into the dorsal wall of the head above the 
brain, 
