Locomotory Limbs 27 



and Troguloidie) the tarsal part is as a rule distinctly' shorter than the tibial part. It will 

 be seen that as regards the structure and form of palpus and the claw Cyphophthalmi 

 approach most nearly to Palpatores and particularly to Ischyropsalidoidaj. 



The locomoturij limbs consist in all known Cyphophthalmi, excepting the adult male of 

 Purcellia illustrans, of six joints besides coxa, viz. trochanter, femur, patella, tibia, meta- 

 tarsus and tarsus. 



Cox?e exhibit a constant difference in size (PI. I., fig. 16; Pi. III., fig. 26; PI. V., fig. 1 h), 

 the fourth pair being, as in all Opiliones, the largest, whilst the first pair is the next in 

 size, and the second and third pair differ but little from each other. In all Laniatores the 

 first pair is the smallest, but Palpatores vary in this respect, the first coxa being not unfre- 

 quently larger than the second and third, as for instance in Troguhcs. But far greater is the 

 difference between coxae observable in Cyphophthalmi, as regards their movability. In Pal- 

 patores coxae are either all immovable, as in I.schyropsalis, Nemastomatoidae and Troguloidae, 

 or they are all movable as in Phalangioidte '^ and amongst Ischyropsalidoidaj in Taracus, 

 Tomicomerns, Sabacon, and Parasabacon, in which case, however, the fourth pair of coxie are 

 less movable than the others, their movement being limited to a slight rotation round their 

 longitudinal axis. In all Laniatores, on the contraiy, the three posterior pairs of coxa? are immov- 

 able and coalesced, the fourth pair coalescing with abdomen, whilst the foremost pair is capable of 

 a slight rotatory movement around its longitudinal axis, whereby their maxillary lobe, which is in 

 itself immovable, can be moved near to or away from the mandibles. It is in fact this point 

 of structure, or rather the difference in the arrangement of the mouth which depends on it, that 

 constitutes one of the essential differences between the two sub-orders. — As regards Cyphophthalmi 

 all previous writers have stated that coxas all coalesce with one another ; but this is not at 

 all the case ; the third and fourth coxae are indeed united, and the fourth coalesces with 

 abdomen, but the first coxa is in all Cyphophthalmi capable of a little movement whereby 

 its maxillary lobe can be brought near to or away from the moiith. So far Cyphophthalmi 

 agree with Laniatores, but in respect of the second coxa Cj'phophthalmi differ amongst them- 

 selves. In Stylocellini it is immovable and coalesced with the third coxa, but in Sironini it 

 is movable, though only to a very small extent. This is a very remarkable fact, as it is 

 without a parallel amongst the other Opiliones, although this order is the most polymorph 

 amongst Ai-achnida, next to Acari. Apart from Opiliones, and omitting Acari with regard 

 to which we do not venture to speak, the condition of coxoe as regards mobility is uniform 

 throughout each order of Arachnida, as may be seen from the following summary. All coxae 

 are movable in Pedipalpi, Palpigradi, Araneae, and — in a small degree — in Chelonethi ; all 

 coxae are immovable in Solifugae ; the first and second are movable in Scorpiones, as shown 

 by Ray Lankester (pp. .522, 523), whilst the third and fourth are united together; and finally 

 in Ricinulei, first, second, and third coxte are coalesced, whilst the fourth pair are movable, 

 as we shall show below. We cannot offer any explanation of the fact of the second pair of 



' In Anelasmocephalus the difference is but small ; in conspicuous. A species from Venezuela, of which we have 



A. obloncjus, where it is the smallest, it amounts only to ^V of seen two specimens from the Museum of Giittingen, occupies 



the length of the tibial part. an intermediate position between Gagrella and Leiobunum in 



- It is well known that in Gagrella Stol. and congeners this respect, as also in regard to the degree of firmness of the 



coxse are adorned with close marginal rows of stout con- integuments. In Sclerosoma and congeners coxse are simi- 



spicuous processes. But this character is not peculiar to the larly adorned with processes, but these are longer, conical, 



genera mentioned. The same structure is found in Leiobunum, and more distant from each other, 

 only that the processes here are very small and but slightly 



4—2 



