410 
Argas persicus 
everted lips, which extends across the camerostomal depression immedi- 
fly anterior to the fold formed by the union of the camerostomal 
megument with the proximal margin of the dorsal part of the basis 
capituli. To the margins of this external opening, the common mouth 
of the paired membranous and hypodermal sacs is attached all round, 
the membranous portion being here directly continuous with the external 
cuticle of the body, while the hypodermal portion joins the general 
hypodermis in a corresponding manner. 
The arrangement of these parts may be briefly described as two 
adjacent invaginations of the body cuticle and hypodermis at the site 
of the external slit, both invaginations possessing a common opening: 
they may aptly be compared to two pairs of breeches with very wide 
and baggy legs, one pair within the other. The legs of the breeches 
are closed at their nether extremities, while the waist-band is represented 
by the external opening of the organ. 
The outer pair of breeches is represented by the hypodermal sacs, 
into which the wide efferent ducts of the laterally-placed glands open, 
one on either side, at the place corresponding to the pocket openings 
of the breeches. 
Into the postei’ior extremity of each of the hypodermal sacs, a small 
bundle of muscle fibres is inserted, the proximal end of which takes 
its origin from the body wall just anterior to the capitular foramen 
(Plate XXVI, figs. 8-9, m. r. gen. org.). These muscles play an important 
part in effecting the restoration of the organ to its resting condition 
after the eversion of the membranous sacs. 
Plate XXVIII shows two transverse sections through the anterior 
part of the body of a female Argas persicus. The first section is 
situated at the level of the fold which is formed by the junction of the 
dorsal face of the capitulum with the integument of the camerostome. 
This fold (cam.) just appears in the central portion of the section, lying 
between the capitulum below, and Gene’s organ above. 
The second section is taken at a level some distance posterior to 
the former, but still anterior to the capitular foramen. In this section, 
the two halves of Gene’s organ appear completely separated, and the 
outer hypodermal sac ( hd.s .) with the glandular portion opening into 
it, is clearly distinguishable. Within this hypodermal sac, a curiously 
folded and crumpled continuous line represents the section of the 
inner chitinous sac ( ct. s., ct. s'.) which presents, in its resting state, 
a collapsed and flattened appearance. The same parts are represented 
in the first section, but this section is intended to show the relations 
