somites.
an, Orifice within which the caudal segments are withdrawn.
E, Extremity of the fifth appendage of the male modified to subserve
copulation.

(Original drawing by Pocock and Pickard-Cambridge.)]

Order 7. Podogona = Ricinulei (see figs. 73 to 76).--Dorsal area of
prosoma furnished with two shields, a larger behind representing,
probably, the tergal elements of the somites, and a smaller in front,
which is freely articulated to the former and folds over the
appendages of the 1st pair. Ventral area without distinct sternal
plates. Appendages of 1st pair, bisegmented, completely chelate.
Appendages of 2nd pair, with their basal segments uniting in the
middle line below the mouth, weakly chelate at apex. Appendages of
3rd, 4th, 5th and 6th pairs similar in form; their basal segments in
contact in the middle line and immovably welded, except those of the
3rd pair, which have been pushed aside so that the bases of the 2nd
and 4th pairs are in contact with each other. A movable membranous
joint between the prosoma and the opisthosoma, the generative aperture
opening upon the ventral side of the membrane. Prae-genital somite
suppressed; the opisthosma consisting of nine segments, whereof the
first and second are almost suppressed and concealed within the joint
between the prosoma and the opisthosoma; the following four large and
manifest, and the remaining three minute and forming a slender
generally-retracted tail like that of _Thelyphonus_. Respiratory
organs tracheal, opening by a pair of spiracles in the prosoma above
the base of the fifth appendage on each side. Intromittent organ of
male placed at the distal end of the appendage of the 5th pair.

[Illustration: FIG. 74.--_Cryptostemma Karschii_, anterior aspect of
the prosoma with the "hood" removed. I to IV, first to fourth
appendages of the prosoma; a, basal segment of the second pair of
appendages meeting its fellow in the middle line (see fig. 75).

(Original drawing by Pocock and Pickard-Cambridge.)]

Family--Cryptostemmidae (_Cryptostemma, Poliochera_), Carboniferous.

_Remarks on the Podogona._--The name given to this small but
remarkable group has reference to the position of the male
intromittent organ (fig. 73, E). They are small degenerate animals
with a relatively firm integument. Not more than four species and
twice that number of specimens are known. They have