1902 Encyclopedia > Arachnida > Arachnida - Order VI: Thelyphonidea - Family II: Tartarides

Arachnida
(Part 22)



(22) ARACHNIDA - ORDER VI: THELYPHONIDEA - FAMILY II: TARTARIDES

This family is nearly allied to the former -- Thelyphonides -- but has a more elongated form. The cephalo-thorax is beak-like in front, and is also divided into two parts or segments; the first comprises the caput, and the coalesced thoracic segments belonging to the first two pairs of legs; the hinder part is the smallest, and comprises the second thoracic segments belonging to the third and fourth pairs, but no grooves or indentations mark the union of the segments, its surface being smooth and glossy. The abdomen is united to the cephalo-thorax by a stout pedicle, and is covered above and below, as in Thelyphonides, with eight or nine transverse, corneous, articulated plates, upper series separated from the lower by a narrow divisional space, covered with a continuous cartilaginous integument. Beneath the fore part, at the hinder margin of the first sub-abdominal segment, a line-like fissure in the median line probably represents the opening to the reproductive organs; near the fore margin of each of the fourth, fifth, and sixth plates, in a transverse line, are two small elongated stigmata, though at first to belong to the respiratory apparatus, but further examination seems to prove them to be , like the eight analogous stigmata in Thelyphonides, imperforate, and probably due to the same cause conjectured in regard to them. two (or four) narrow slits, placed two and two symmetrically on each side of the genital aperture at the fore margin of the first and second segments, but very difficult to be correctly ascertained, are probably the external openings to the respiratory organs; these points, however, can hardly yet be said to be satisfactorily determined. Two or three very narrow corneous rings, or post-abdominal articulations, support a caudal appendage, either slender, cylindrical, and bi-articulate, or of a largish, peculiar, sub-triangular form, articulated to a small foot-stalk. Eyes none, no traces even of eyes being visible. The falces are strong, of a flattened cylindrical form, deeper than broad, projecting in the plane of the cephalo-thorax, and terminating with a sharp, curved, movable fang at their upper extremity, the lower extremity being rather pointedly prominent.

The palpi are very strong, five-jointed, and each issues from a long, nearly cylindrical basal joint to maxilla, the inner fore corner of which is prolonged into a sharp, strong point; the other joints are armed variously with teeth, and the final, or digital, joint in one species has a longish, but not very strong, spine beneath it, terminating with a small, apparently movable, curved claw. In these palpi we see a marked transition from the more apparent didactyle nature of those of Thelyphonides to those of the Phrynides, removing them further than the former, in this respect, from the Scorpiones.

The legs appear very similar to those of Thelyphonus; they are seven-jointed; those of the first pair are slender and evidently palpiform, their tarsi are composed each of several (apparentlyten) minute articulations, and devoid of terminal claws. Those of the other three pairs are apparently inarticulate, and each ends with three simple curved claws, of which the inferior one is the smallest and most sharply bent; the femora of these three pairs are all strong, those of the fourth pair inordinately so. The sternal plates are very similar to those of Thelyphonus, but the hinder one is not so much developed, and the central corneous spot in not visible.





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