Organs of Excretion 49 



length, with an adherent piece of the bladder, which certainly was too small to give an idea 

 of the size of the bladder, but it was large enough to show us, who were familiar with 

 the relation between the tubes and the bladders, that the tube does open into a bladdei'. 

 Under the circumstances we cannot of course say with perfect certainty where the orifices 

 of the bladders are situated, but on a dermoskeleton of a female Purcellia, which had 

 been cleaned \>y means of caustic potash, we found a pair of holes, which we cannot doubt 

 are the openings of the urinary bladders ; they are placed between arculi genitales and 

 the most proximal part of the third pair of coxje, and we have reason to believe that both 

 in the male Purcellia and in the other genera these openings are situated in or near the 

 same place. It follows that in this point of structure Cyphojahthalmi agree essentially with 

 Palpatores. 



In conclusion we would say a few words with regard to the function of these so-called 

 coxal glands in Opiliones, and their homological relations to the excretory glands in other 

 Condylopoda. One of us, who, as far as we are aware, was the first to find them in any 

 Arachnidean, viz. in Opiliones Laniatores, described them as " Organs of Excretion, Kidneys 

 or Malpighian tubes." There can be no doubt that in Opiliones they are really excretory 

 organs, because such organs would otherwise be entirely absent from these animals. This 

 is also the view taken by Loman in his last paper on these organs (c), although he had 

 attempted in vain to demonstrate the presence of urinary products in them. "Coxal glands" 

 have been found in all orders of Arachnida (amongst Acari, at least in the sub-order 

 Notostigmata, see With, p. 164), and also in Xiphosura. Many authors consider them to be 

 the homologues of the "segmental organs" (the nephridia) of Annelida. We do not venture 

 to follow this opinion for this reason, amongst others, that it appears to us too hazardous 

 in view of the great distance which, according to our opinion, exists between Annelida and 

 Condylopoda. We may on this point refer to what one of us, H. J. Hansen, replied to 

 the question addressed to him amongst others by Natural Science, viz. " Are the Ar- 

 thropoda a natural group?" {Nat. Sc. 1897, pp. 97 — 117). In discussing the homology 

 of these organs, we prefer on the contrary to confine ourselves to Condylopoda. 



It is very generally said that though the " coxal glands " in younger or not full-grown 

 animals possess an open outlet on the surface of the body, yet in adult individuals these 

 openings are closed. We must confess to entertaining very grave doubts concerning the cor- 

 rectness of such statements, but we prefer not to enter further into that question on this 

 occasion. As regards the position of these openings, whether they are ultimately closed or 

 not, we refer to the paper by Sturany on the coxal glands, in which he has collected all that 

 at that time (1890) was known on the subject. He knew that their openings are situated 

 at the fifth pair of limbs (the third pair of legs) in Scorpiones, Aranese Theraphosae, and 

 in " Phalangioidse," which latter term he employs for Opiliones ; but as he found at the 

 same time that in Aranese verse, and "probably," as he says, also in Solifugas', they are 

 placed opposite the third pair of limbs, he adds that " the question now arises whether 

 we are to look upon the coxal glands as representing one nephridium or more'"," a 

 question which we should pi-efer to formulate thus : are these organs to be considered 

 fully homologous in all Arachnida and Xiphosura ? In seeking a reply to this question it 



' This was afterwards confirmed by Bernard who (p. 877) ^ " Es entsteht nun die Frage, ob wir in den Coxaldriisen 



states that in Sohfuga they are situated between the coxae ein einziges [Nephridium] oder derer mehrere zu suchen 

 of the third and fourth pairs of Umbs. haben." 



