240 B- H. BuxTON, 



being always clearly raarked off between tlie other two in both 

 species exarained. 



BöRNEE figures tliese cylindrical basophil cells and remarks that 

 they are different from the cells of the coxal glands in Thelijphonus', 

 and also from tliose of tlie palpigrades (Koenenia). He does not 

 however appear to liave noticed that these cylindrical cells are 

 confined to one part of the labyrinth but speaks as if they were 

 the only kind of excretory cells found in the coxal gland. 



With regard to the blood supply, there runs parallel with the 

 labyrinth a large blood sinus (VS) lying ventral to the labyrinth 

 coils (photos 12, 12a) alongside of and just internal to the ventral 

 tubule of the labyrinth. From the sinus small branches run in among 

 the coils of the labyrinth so that the tubules are all bathed in the 

 circulating fluid (photo 11). The sinus runs along the whole length 

 of the labyrinth and on reaching the saccule anteriorly, breaks up 

 to form the glomeruli which hang into the saccule. Photograph 11 

 shows the relation of the ventral sinus to the labyrinth tubule in 

 transverse section. 



3. Spiders. 



Among the Spiders there is great Variation in the appearance 

 of the coxal glands. It has already been remarked that in the 

 Theraphosids there are two saccules and two difterent outlets, but 

 only one of each in the Araneae verae. The labyrinth of the 

 Theraphosids is very complicated but in the higher spiders becomes 

 more and more simplified as we pass from the Theraphosids to the 

 Dysderids and Sicariids, and from these through the hunting spiders, 

 Lycosids and Thomisids, to the highest of the web Spinners like 

 the Epeirids and Theridiids, in which the labyrinth has become 

 reduced to such an extent that it is no longer recognizable as such. 

 The reduced condition of the coxal glands in the higher spiders 

 has been observed by Beetkau and Stueany, and referred by them 

 to degeneration , but it seems more probable that it is a case of 

 simplification with increased efficiency of the remainder, since the 

 saccule on which may be, the most important part of the work falls, 

 is still in good working order. The writers do not mention the 

 saccule and probably overlooked it. Even Beuntz, who is generally 

 very particular about the saccule, does not seem to recognise it in 

 the higher spiders, and in speaking of elimination of carmine by 

 them, mentions only the nephrocytes (amoeboid connective tissue 

 cells) and the malpighian tubules. Beenaed (1897) suggests that 



