Sub-order b. Amblypygi.—Prosoma wider than long, covered above by a single shield bearing median and lateral eyes, which have diplostichous ommatea. Sternal area broad, with prosternal, two mesosternal, and metasternal plates, the prosternum projecting forwards beneath the coxae of the 2nd pair of appendages. Appendages of 2nd pair folding in a horizontal plane; their basal segments freely movable; claw free or fused; basal segments of 4th and 5th pairs widely separated by the sternal area; appendages of 3rd pair with all the segments except the proximal three, forming a many-jointed flagellum. Opisthosoma without post-anal sclerite and posterior caudal elongation: with frequently a pair of small lobate appendages on the sternum of the 3rd somite. Respiratory organs, as in Urotricha.
Family—Phrynichidae (Phrynichus, Damon).
” Admetidae (Admetus, Heterophrynus).
” Charontidae (Charon, Sarax).
(Family ?)—*Graeophonus.
| Fig. 59.—Schizomus crassicaudatus, one of the Pedipalpi. Lateral view of a male. II to VI, the prosomatic appendages, the first being concealed (see fig. 58); 5, the fifth, and 11, the eleventh tergites of the opisthosoma; pa, the conical post-anal lobe. |
| (Original as preceding.) |
Remarks.—The Pedipalpi are confined to the tropics and warmer temperate regions of both hemispheres. Fossil forms occur in the Carboniferous. The small forms known as Schizomus and Hubbardia are of special interest from a morphological point of view. The Pedipalpi have no poison glands. (Reference to literature (29).)
| Fig. 60.—Liphistius desultor, Schiödte, one of the Araneae Mesothelae. Dorsal view. I to VI, the prosomatic appendages; 4, 5, 6, the fourth, fifth and sixth tergites of the opisthosoma. Between the bases of the sixth pair of limbs and behind the prosomatic carapace is seen the tergite of the small prae-genital somite. |
| (Original by Pickard-Cambridge and Pocock.) |
Order 3. Araneae (figs. 60 to 64.).—Prosoma covered with a single shield and typically furnished with median and lateral eyes of diplostichous structure, as in the Amblypygi. The sternal surface wide, continuously chitinized, but with prosternal and metasternal elements generally distinguishable at the anterior and posterior ends respectively of the large mesosternurm. Prosternum underlying the proboscis. Appendages of 1st pair have two segments, as in Pedipalpi, but are furnished with poison gland, and are retroverts. Appendages of 2nd pair not underlying the mouth, but freely movable and, except in primitive forms, furnished with a maxillary lobe; the rest of the limb like the legs, tipped with a single claw and quite unmodified (except in ♂). Remaining pairs of appendages similar in form and function, each tipped with two or three claws. Opisthosoma when segmented showing the same number of somites as in the Pedipalpi; usually unsegmented, the prae-genital somite constricted to form the waist; the appendages of its 3rd and 4th somites retained as spinning mammillae. Respiratory organs (see fig. 63, stg), as in the Amblypygi, or with the posterior pair, rarely the anterior pair as well, replaced by tracheal tubes. Intromittent organ of male in the apical segment of the 2nd prosomatic appendage.
 | Fig. 61.—Liphistius desultor. Ventralview with the prosomatic appendages cutshort excepting the chelicerae (1) whosesharp retroverts are seen. Between thebases of the prosomatic limbs an anteriorand a posterior sternal plate (black) areseen. 1, The sternum of the first opisthosomaticor genital somite covering thegenital aperture and the first pair of lung-sacs.In front of it the narrow waist isformed by the soft sternal area of thepraegenital somite; 2, the sternite of thesecond opisthosomatic somite coveringthe posterior pair of lung-sacs; 3 and 4,the spinning appendages (limbs) of theopisthosoma; a, inner, b, outer ramus ofthe appendage; 11, sternite of the eleventhsomite of the opisthosoma: in front of itother rudimentary sternites; an, anus. |
| (Original as above.) |