254 B- H. Büxton, 



jected towards the outlet of the rostrum and the prey held by the 

 chelicerae in front of the rostrum. 



The apparatus for forcibly ejecting the fluid is there. and, the 

 chitinous sheath through which the stream passes would keep it in 

 the right direction, since in the solifugae the mouth parts, instead 

 of being situated ventrally, as in the spiders and pedipalps, are 

 directed straight forward, the rostrum (R) forming a sucking Chamber 

 (KS) in front of the mouth proper, and extending anteriorly between 

 the chelicerae (photo 39). 



The solifugae have a bad reputation in many places as poi- 

 sonous animals, but no deflnite poison glands, such as exist in spiders 

 and scorpions, have ever been found, Pocock suggests that the 

 poison may exude from small setal glands situated in the teeth of 

 the chelicerae, but I do not know that this has ever been demon- 

 strated, and it seems more probable that the poison, if there is any, 

 is the product of the coxal gland. 



When the coxal glands were first observed in the solifugae 

 they were taken for poison glands (in: Cambridge nat. History), 

 but this view was refuted and the glands are now considered to 

 be excretory, and homologous with the coxal glands of other arach- 

 nids. However it is possible that the older observers were not so 

 far wrong after all. 



In any case the coxal gland would appear to act as a salivary 

 gland. In the spiders and scorpions special salivary glands have 

 been evolved on the coxal joints of those appendages which are 

 situated dosest to the mouth and do most of the masticatory work. 

 Such salivary or buccal glands in the spiders are localised at the 

 base of the coxal Joint of the second appendage^ and in the scorpions 

 of the third and fourth appendages, but are quite independent of 

 the coxal or poison glands. There are no such separate buccal 

 glands in the solifugae which affords an additional reason for sup- 

 posing that the coxal glands perform the duty of salivation. 



Briefly then the spiders and scorpions have three distinct sets 

 of glands, poison, salivary and excretory, but in the solifugae all 

 these duties are performed by the coxal glands, parts of which are 

 specially modified for the purpose. 



Before concluding, a few additional observations may be recorded. 

 With regard to the saccule; in some specimens of Paragaleodes, on 

 one side of the animal the coUecting tubule is open, and its course 

 can be readily traced from the saccule to the labyrinth sac (photo 41, 



