188 Transactions. — Zoology. 



In some of the Araneidea tlie spiracular plates are four in number (f. 15m, n), 

 but for the most part tliere are only two ; where more than two are present it 

 has been found that the posterior pair are connected with trachece, the anterior 

 ones with pulmo-hranchice. In some few spiders a kind of supernumerary 

 spiracular slit or opening is visible, near to the ordinary one, but not always 

 similarly placed. Cambridgea quadrifasciata, L. Koch, as described below, is 

 an instance of this, where, when the spider is looked at in profile (f. 3p), it is 

 above the ordinary one on each side (see also post, description of Plate VI., f. 2tt). 



The Falces, two in number (f 5d, IGd, 3x), are one-jointed, and articulated 

 beneath the fore part of the cephalo-thorax ; they are generally armed, more or 

 less, with teeth on their inner sides, and each terminates with a moveable curved 

 fang, which, when not in use, is folded down either across the inner side of the 

 extremity of the falx, as with most spiders (f. 5d), or backwai-ds along its 

 length as in one family — Theraphosides (£ lor) ; by means of these fangs a 

 poison secreted within the caput is instilled into the wound made by them, 

 proving, no doubt, fatal to the spider's prey, and often nearly so — in the 

 genus Lathrodectus — to human beings ; for instance, Lathrodectvs katipo, 

 LI. Powell, vide Trans. N.Z. Inst, III., pp. 56-59; also, F. W. Wright, id., n., 

 pp. 81-84 ; and W. L. BuUer, id., Ill, pp. 29-34. 



The Eyes (£ 12, 19) — as at present known — are two, four, six, or eight in 

 number, but by far the larger proportion have eight eyes ; two known species 

 alone have four — Miagrammopes, Cambr., and Tetrablemma, id. — and only one 

 species — No2}s, Macleay — has yet been described with two ; the eyes are 

 variously disposed, but always symmetrically on the fore part of the caput — 

 i.e., the cephalic segment — which is generally well defined by an oblique 

 indentation and constriction on either side of the anterior part of the cephalo- 

 thorax (f 3r, 4&, and 166). The number and general position of the eyes form 

 one valuable character for the formation of genera, while their relative size is 

 strongly specific. 



The Legs, eight in number, are articulated to a kind of separate plate 

 (sternum, f. 2f, and 15^), which forms the underside of the cephalo-thorax ; 

 in one genus (Miagrammopes, Cambr.) from Ceylon, no sternum, properly so 

 called, exists, the legs being articulated to the continuous underside of the 

 cephalo-thorax. 



Except in one or two species the legs are seven-jointed, and variously 

 furnished with hairs, bristles, and spines, each tarsus ending with two or three 

 claws, generally more or less bent or curved, and commonly pectinated, or 

 finely denticulate ; these claws are used as hooks, to give a tension to the lines 

 of their snares by holding on and straining upon them. The spines and 

 bristles also are, in many cases, used in the construction of the silken snares, 

 in which spiders entra^j their prey ; and the males of some species have a 



