26 Mandihles and their Palps 



of it in Cyphophthalmi is as follows. The joints are slender, cylindrical, a little thicker 

 towards the apex, excepting the tarsal part (PI. I., fig. 1 j, e) (the fifth joint of the palpus), 

 which always approaches to the fusiform shape ; the trochanterial part («) is bent upwards, whilst 

 the femoral part (6) is bent a little downwards ; the others are nearly straight. The tro- 

 chanterial part (a) is distinguished by a proportionately considerable length in comparison with 

 the trochanters of the legs, and in the great majority of genera the femoral part is the 

 longest of them all, whilst the tarsal part is distinctly shorter than the tibial part. A notable 

 exception from this general structure of palpus is met with in Ogovia (PI. II., fig. 6 b), where 

 the tarsal part is longer than the tibial portion and in fact the longest of all, whilst the 

 femoral part (b) is strongly compressed and proportionately short, of about the same length as 

 the proportionately strong trochanterial part. Generally palpi are slender and without armature; 

 Purcellia alone offers an exception to this rule (PI. IV., fig. If) through the presence of a 

 small process on the under side of the trochanterial part. In all Cyphophthalmi hitherto 

 known the tarsal part terminates in a small claw (PI. I., fig. Ij, f), which is always quite 

 plain, without teeth, almost straight, and scarcely tapering towards the abruptly rounded apex. 



It is generally recognized that the structure of palpi is of considerable systematic value 

 within the order Ojjiliones. In Laniatores they are variously armed, powerful and adapted 

 for the predatory habits of the animals, which caused Thorell to choose the name of 

 Laniatores for this sub-order, carrying as they do an always large, generally even very large, 

 curved and jaointed claw, which can be clapped against the tarsal part and thus serves to 

 catch the prey. In Palpatores on the contrary palpus is always much weaker, as a rule slender, 

 and very rarely armed with fairly strong spines {Amopamn W. S.). The claw, which is not 

 always present, is capable of but little movement, and as a rule only slightly longer than the 

 diameter of the tarsal part ; it is most developed in Phalangioidte, where it is convex, a 

 little curved and tapering very much towards the apex. In Nemastomatoidaj and Troguloidsp. 

 palpus is very slender and without a claw. The genera belonging to Ischyropsalidoidas exhibit 

 considerable differences in point of structure, and this is the case also as regards palpus. In 

 Ischyropsalis, Taracus, and Tomicomerios, palpus is slender, and carries a very small slender 

 claw', which is almost straight and scarcely diminishes in thickness towards the apex, which 

 is abruptly rounded. In Sabacoii and Purasahacon crassipalpis the palpi are, on the contrary, 

 rather stout in proportion to their length, and the tibial part is notably thicker than the other 

 joints, besides which these genera offer a peculiarity, in which they differ from all other 

 Opiliones, viz. that the tarsal part when curved is raised from its horizontal position, and 

 after describing a wide arc comes to rest in a rather deep excavation on the apical portion of 

 the inner- side of the tibial part. The joints are clothed — the two apical ones closely — with 

 long hairs, of which many are plumose, whilst a few particularly strong ones exhibit a peculiar, 

 as it were articulated, appearance ; a claw is altogether wanting. In those Palpatores which 

 have a well-developed claw (Phalangioid»), the tarsal pai-t is noticeably longer than the tibial 

 part, but where the claw is very weak, or none is found (Ischyropsalidoidse, Nemastomatoidse 



' That C. L. Koch and all subsequent writers have denied Tomicomerus where it is only half as long as the surrounding 



the existence of a claw in Ischyropsalis is due not only to its hairs. 



small size, but quite as much to the circumstance that the - The original specimen of Koch's Xemastoma crassipalpe 



tarsal part is rather densely covered towards the apex with ( = Pnras?(6nco?i crussiya/^is) possessed only one palpus, which 



hairs, which are but little shorter than the small claw. In was torn off. According to L. Koch {b, pp. ill, 112) the 



Taracus the latter is even less conspicuous on account of its excavation on the tibial part is found on the inner side, 

 very light colour ; it is still more difficult to see it in 



