40 



snme stage of development, as the femur of Ihe first pair in Chelifer Geof., and 

 that the femurs of the first as well as of the fourth has attained its final stage in 

 Chiridhim Menge. 



The two last pair of legs of Chthonius C. K. are remarkable for their powerfuU 

 compressed femurs, to which animals of this genus owe their jumping habits, as 

 well as for the comparatively well developed articulation between the trochantin 

 and the rest of the femur (PI. I, fig. 1 in. f). The trochantin is about half as long 

 as the whole femur and ends with an articulate cavity, which faces forwards and 

 outwards; if we follow the articulate membrane between the two joints, it will 

 be seen to be curved towards the base anteriorly, but away from it posteriorly i 

 the mobility is probably very limited , corresponding to the narrow articulate 

 membrane. 



The limitation between the trochantin and the distal ])ortion of the femur 

 seems to be a mere strictuni in the Obisiidae Hans. In Blotbrus spelaeiis Sch. the 

 two portions of the long and slender femur are of almost equal length ; the greatest 

 thickness is attained just in front of the articulation. In Roncus alpiiuis L. K. and 

 Ohisiiim nmscorum Leach the trochantin of the fairly compressed femur is almost 

 half as long as this, and its strictum perpendicular on the longitudinal axis of the 

 femur. In most species of the Pseiidobisiinae Hans, the trochantin is seldom half 

 as long as, in fact as a rule it is only one third as long as the whole femur or 

 less (21. pi. X, figs, le and 2g); the articulation is seldom perpendicular on the 

 longitudinal axis, but most often more or less oblique, so that the ventral margin 

 becomes much longer than the dorsal, a structural feature in common with most 

 of the Panctenodactgli (PI. I, fig. 4 i). 



The fourth pair of the femurs does not in the Garypidae Hans, provide 

 characters of great importance; the exceedingly narrow articulation is always 

 oblique, so that the ventral margin of the trochantin is several times longer than 

 the dorsal one; this joint is seldom as in Gargpinus nobilis n. sp. (PI. II, fig. 8 g) in 

 length equal to one third or more of the whole femur, but as a rule 4 — 5 times 

 shorter (cf. pi. II, fig. 1 d of Garypiis irrugatus Sim.). The shape of the femur 

 varies according to the relation between the length and the depth. Garypns bicornis 

 Bks. has according to Banks (50. p. 9) no trochantin in the fourth pair of legs. 



The trochantin of the Cheliferinae Sim. is at least in Chelifer GeoL in all respects 

 similar to that of the Garypidae Hans, by its rather short ventral margin, which is 

 much longer than the dorsal on account of the oblique articulation; the variations in 

 length between the species are scarcely so pronounced as in the foregoing family. 

 In Pseudochiridiiim Thorellii n. sp. (PI. IV, fig. 12 f) the long stalked femur has a 

 trochantin, which has an almost perpendicular articulation and in length e([uals 

 more than one third of the whole femur; only the ventral half of the articulate 

 membrane is present, the dorsal is represented by a symphysis. The femur of the 

 fourth pair in Chiridium Menge shows no trace of a trochantin, but is four times 

 longer than deep and provided with a long stalk. A "lyriform" fissure probably 



