392 
Avgas persicus 
As has been shown, the pharyngeal muscles form two series—the 
dilator muscles ( m.d.ph .; see also Part II, Text-tigs. 2 and 3) and the 
constrictor muscles. The dilator muscles of the pharynx consist of six 
longitudinal series of stout bands which radiate from their points of 
insertion on the external surface of the pharyngeal wall to their basal 
attachments; viz. the ventral surface of the subcheliceral plate in the 
case of the dorsal series, and the lateral walls of the basis capituli in the 
Fig. 4. Argus persicus ? . Horizontal section through the basis capituli, showing the 
origins and insertions of the lateral dilator muscles of the pharynx, and the muscles 
of the basal article of the palp. The smaller figure is taken from a section which 
passes through the antero-dorsal portion of the pharyngeal wall, and shows some of 
the dorsal dilator and constrictor muscles of the pharynx. 
b.c. basis capituli; br. brain; buc.cav. buccal cavity; cam./, camerostomal fold; 
m.abd.p. abductor muscle of palp; m.add.p. adductor muscle of palp; m.c.ph. 
constrictor muscles of pharynx; m. d.ph. dilator muscles of pharynx; m. l.c. levator 
muscles of capitulum; oes. oesophagus; pli. pharynx; sh. ch. sheath of chelicera; 
sub. ch. p. sub-cheliceral plate. 
