32 MoutJi hi Palpatores 



basal portion is much shorter than the more distal one and immovably connected with coxa 

 itself, forming merely a ridge alongside the anterior (or interior) side of the proximal part 

 of coxa; it is consequently not readily distinguished, particularly as it is situated at a higher 

 level, and therefore it has not hitherto been recognized. At the same time the distal one of 

 the two chitinized portions is differently shaped in the two groups ; in Phalangioidee its 

 two dimensions, measured respectively from the base to the distal margin, and from the 

 posterior to the anterior margin, are not greatly different ; but in Ischyropsalis, Nemasto- 

 matoidsB and Troguloidae, the latter of these two dimensions is much longer than the former, 

 in accordance with which the mouth is of a somewhat elongated form. In this respect 

 TroguloidaD show the greatest divergence from Phalangioidye, while Ischyropsalis exhibits the 

 smallest difference from that family ; but it is a remarkable circumstance that whilst Ischyrop- 

 salis agrees with Nemastomatoidaj and Troguloidce as regards the immovability of the proximal 

 portion of the maxillary lobe, the other genera of Ischyropsalidoidie, viz. Taracus, Toniicomerus, 

 Sabacon, and Parasahacon, agree with Phalangioidse in this respect, the basal portion of the 

 maxillary lobe being movably connected with coxa, as in that family. It will be seen that 

 the differences between the several genera of Palpatores in respect of the movability or 

 immovability of the proximal portion of the maxillary lobe of the first pair of coxas do not 

 coincide entirely with the limits of the families. But there exists a correlation between the 

 movability or the contrary of the proximal portion of the maxillary lobe in question, and the 

 movability of coxae ; they are either both movable or both immovable, and the reason is 

 no doubt mechanical. The fact is that, whilst in Laniatores and Cyphophthalmi the first pair 

 of coxae are capable only of a minimum of movement, their movability — and the movability 

 of the three other pairs — in Phalangioids and the genera of Ischyropsalidoidw above enumerated 

 is manifestly sufficiently considerable to be of some, though scarcely much, importance for 

 the use of the legs in locomotion. It is clear that if, under these circumstances, the con- 

 nection between the maxillary lobe and the first pair of coxa3 admits of some movement, the 

 latter can be moved without interfering with the movements of the maxillary lobes, that is of 

 the parts of the mouth. 



In Palpatores labium sternale (woodcuts figs. B and I, i) projects between the maxillary 

 lobes of the first pair of coxse, and is joined to the latter to a greater or smaller extent, 

 in Phalangioidse through almost half its length, in Troguloidse through the whole of it. 

 Labium sternale exhibits a good deal of difference in respect of shape and of its relation to 

 the rest of sternum ; as, however, we have treated of this matter in connection with sternum, 

 we may here refer the reader to our remarks on the latter. 



Behind labium, that is to sa}', really outside the mouth, we find tlie maxillary lobes of the 

 second pair of coxce. In the Palpatores they are of rather elongated shape. They do not 

 terminate in soft cushions as the other parts of the mouth do. In Phalangioids; they (wood- 

 cuts figs. A and B, lex") are very movable and execute quick, oscillating movements, which 

 are easily seen when the captive animal uses the mouth ; when at rest they occupy a slanting 

 position underneath the maxillary lobes of the first pair and labium, pressed against these 

 parts of the mouth. In Ischyropsalidoidse the maxillary lobes of the second pair of coxse 

 have a downward direction and are much less developed than in Phalangioid;e. In Ischyrop- 

 salis their shape is more oblong conical, and they are undoubtedly capable of movement ; 

 in Taracus they resemble a low rounded cone and are perhaps movable ; in Tomicomerus they 

 are shaped like low rounded tubercles or thick cones, and are scarcely capable of movement ; 



