NOTES ON THE ANATOMY OF ARACHNIDS 



B. H. BUXTON 



EIGHT DIAGRAMS AND THREE PLATES 



PART I 



THE COXAL GLANDS OF THE ARACHNIDS 



This paper is a continuation and extension of one published 

 in the Zoologische Jahrbiicher of July, 1913, since which time 

 I have had an opportunity of adding to the number of species 

 examined. 



It was shown in the previous paper that there are two very 

 distinct groups of the arachnids as regards the construction of 

 the coxal glands. In Group I may be placed the scorpions, 

 pedipalps and spiders, which have been more particularly 

 studied. The Phalangids certainly, and the Pseudo scorpions 

 most probably, also belong to this group, but as they have not 

 been made a subject of special study, will not be described in 

 detail. In Group II were placed the Solifugae, and to these 

 can now be added the Palpigrades. 



The component parts of the coxal glands of Group I consist 

 of (1) the terminal sac, or saccule, lined with a very delicate 

 cubical or flattened epithelium which has the property of ex- 

 creting solid particles such as carmine when injected subcuta- 

 neously. Solid particles, probably urates, can also frequently 

 be observed normally in the cells lining the walls of the saccule. 

 From (2) the saccule, a short duct, or collecting tubule, leads 

 into (3) the labjTinth, which consists of a single, usuall}^ coiled, 

 tube, the walls of which are lined with excretory epithelium 

 having the usual striated base indicative of excretory functions, 

 but solid particles are never excreted by these cells. At the 

 distal end of the labjTinth there is sometimes a vesicular swell- 

 ing which can be regarded as (4) the bladder; and from the 



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JOURNAL OF MORPHOLOGY, VOL. 29, NO. 1 

 JUNE, 1917 



