Family—Cryptostemmidae (Cryptostemma, Poliochera), Carboniferous.
 | Fig. 74.—Cryptostemma Karschii,anterior aspect of the prosoma withthe “hood” removed. I to IV, firstto fourth appendages of the prosoma;a, basal segment of the second pairof appendages meeting its fellow inthe middle line (see fig. 75). |
| (Original drawing by Pocock andPickard-Cambridge.) |
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 been found in West Africa and South America. A fact of special interest in regard to them is that the genus Poliochera, from the Coal Measures, appears to be a member of the same group. The name Cryptostemma, given to the first-known genus of the order, described by Guérin-Méneville, refers to the supposed concealment of the eyes by the movable cephalic sclerite. Reference to literature (38).
 | Fig. 75.—Cryptostemma Karschii, one of the Podogona. Ventral view. |
I to VI, The six pairs of appendages of the prosoma, the last three cut short. 1, 2, 3, 4, The four somites of the opisthosoma. a. Visible hood overhanging the first pair of appendages. b, Position of the genital orifice. c, Part of 3rd appendage. d, Fourth segment of 2nd appendage. Observe that the basal segment of appendage III does not meet its fellow in the middle line. | |
| (Original drawing by Pocock and Pickard-Cambridge.) |
| Fig. 76.—Cryptostemma Karschii. Extremity of the fifth pair of appendages of the female for comparison with that of the male E in fig. 73. |
Order 8. Opilione (see fig. 77).—Dorsal area of prosoma covered by a single shield usually bearing a pair of eyes. Sternal elements much reduced. Appendages of 1st pair large, three segmented and completely chelate; of 2nd pair either simple and pediform, or prehensile and subchelate; of remaining four pairs, similar in form, ambulatory in function; the basal segment of the 2nd, 3rd and sometimes of the 4th pairs of appendages furnished with sterno-coxal (maxillary) lobe. Opisthosoma confluent throughout its breadth with the prosoma, with the dorsal plate of which its anterior tergal plates are more or less fused; at most ten opisthosomatic somites traceable; the generative aperture thrust far forwards between the basal segments of the 6th appendages. Prae-genital somite suppressed. Respiratory organs tracheal, opening by a pair of stigmata situated immediately behind the basal segments of the 6th pair of appendages on what is probably the sternum of the 2nd opisthosomatic somite and also in some cases upon the 5th segment of the legs.
Intromittent organ of male lying within the genital orifice.
Sub-order a. Laniatores.—Orifice of foetid glands opening above the coxa of the 4th appendage, not raised upon a tubercle. Orifice of coxal gland situated just behind that of the foetid gland. Sternal plate of prosoma long and narrow, with a distinct prosternal element underlying the mouth. Coxae of 4th, 5th and 6th appendages immovable. Appendages of 2nd pair, strong, usually prehensile and spiny. Genital orifice covered by an operculum.
Families—Gonoleptidae (Gonoleptes, Goniasoma).
Biantidae (Biantes).