50 '' Coxal Glands" in Arachnida 



must, however, be borne in mind, that Aranese veras and Solifugai are by no means the 

 only Arachnida in which these orifices are known to be situated in another place than at 

 or opposite the fifth pair of limbs. We have already stated that in Opiliones Laniatores 

 their place is above the fourth pair of limbs. It is true that we would not venture to 

 maintain absolutely that this place in reality belongs to another segment than that to 

 which the fifth pair of limbs belong, behind which these glands open in Palpatores and 

 most probably in Cyphophthalmi. Every indication of a division of cephalothorax into 

 segments having disappeared in Laniatores there is a possibility, though not much proba- 

 bility, that the place where the opening is situated belongs to the first thoracic segment 

 which carries the fifth pair of limbs (the third pair of legs). But on the other side we 

 should be still less inclined to look upon this question as answered in the affirmative by 

 the position of the orifices in Laniatores. There remains, however, the case of Palpigradi 

 {Koeiieiua) where the matter is altogether beyond dispute: Grassi has already mentioned (p. Kjl, 

 fig. 13) that he had found a paired long tubular gland, which "perhaps" had its orifice 

 in front of the third pair of limbs. Grassi looked upon this pair of glands as corresponding 

 to Krohn's glands, that is the odoriferous glands in Opiliones Palpatores. In the course 

 of the investigations we carried out in preparing our little paper on this type, on which 

 occasion we do not otherwise attempt to study the interior anatomy, we were once fortunate 

 enough to see this gland and found that according to its structure it was, as we expressed 

 ourselves, " exactly the same as the excretory ones in Opiliones." Partly relying on this 

 and partly, though in a lesser degree, on the strength of Grassi's suggestion concerning 

 the position of the orifices, which we had not the good luck to see, we stated concerning 

 this pair of glands that " there can scarcely be any doubt that it corresponds to the excretory 

 glands which in the higher Arachnida... just have their orifices on the sides of the cephalo- 

 thorax, and not — like the Malpighian tubes of the Insects — in the rectum." Miss Aug. Rucker 

 (p. G26), who does not seem to have understood our opinion concerning these glands, as 

 she does not mention it, though she was acquainted with our paper, has demonstrated 

 that they " terminate between the second and third pair of appendages." But in Palpigradi 

 the thoracic segments which carry the fifth and sixth pairs of limbs are plainly separated 

 from that unsegmented portion (the head) which carries the first four pairs of limbs, on 

 which these glands therefore open. In view of this fact it is beyond dispute that these 

 glands in Koe)ien{a cannot be ftiUi/ homologous with those which in other Arachnida open 

 at the fifth pair of limbs. 



According to our view there are consequently in Arachnida' (apart from Acari) two 

 morphologically different sets of excretory organs, one opening behind the third pair of 

 limbs which is developed in Palpigradi, Pedipalpi", Solifugas, Araneae verse, and Opiliones 

 Laniatores, and another opening at the fifth jDair of limbs which is developed in Scorpiones, 

 Chelouethi (Pseudo-scorpiones)*, Araneaj Theraphosag and Opiliones Palpatores, and probably 

 Cyphophthalmi ^ 



• The excretory organs of Eicinulei are not known, as the third pair of limbs in Amblypygi {Plinjniis). — They have 



indeed is the case with nearly tlie whole of tlieir internal not been found in Tartarides {Si-hhomus). 

 structure. '■< Bernard has found the openings behind the coxae of the 



■^ In Uropygi (Thehjphonus) Adensanier found that these fifth pair of limbs, 

 organs open at the base of the coxa; of the third pair of limbs, ■* It was only after the text of our treatise was finished 



whilst according to Laurie the orifices are placed behind the that we became acquainted with Gough's paper on the 



latter; Tarnani also observed their orifices in embryos behind development of Admetus pumilio (a species of Amblypygi). 



the third pair of limbs. — Bernard found the openings behind Like his predecessors he has found " coxal glands" at the 



