Coxal glauds of the Arachuids. 



259 



tall columnar cells, containing- basophil granules; cells tlierefore 

 whicli appear to have secretory functions (pliotos 47 to 47d LM). 



The nephridia of segments six 

 and seven, on legs four and five, 

 have become modified from type in 

 the sense that the labyrinth is 

 very extensive; its tubules forming- 

 complicated twists and turns, but 

 the modified secretory portion of the 

 labyrinth is entirely lost. The 

 vesicle has also disappeared, so that 

 from the collecting tubule, to the 

 exit tubiile there is an iinbroken 

 Stretch of labyrinth with striated 

 cells, as in the scorpions, pedipalps 

 and theraphosid spiders. 



In the modified nephridia of the 

 first three and last three leg-s on 

 the contrary it is the striated portion 

 of the labyrinth which is entirely 

 missing-. The short collecting tubule 

 passes directly into a tubule lined 

 with cells resembling those of the 

 modified part of the typical labjTinth ; 

 this tubule proceeding straight to 

 the exit tubule without any vesicular 

 enlargement (photo 49 NM). 



The modified nephridium of the 

 secoud appendage, known as the 



salivary gland, presents some very fuunel bearing collecting tubule (CD. 



remarkable features. The saccule The striated part {CL) coils upou 



. ,.,1 itselt, and at the bend in close 



and collecting tubule can readily be proximity to the collecting tubule, 



found and recognised in photos 48, t^?;« i« ^ f^^o^'t stjetch Hued with 



'^ ,, . epithehum of a secretory nature (ZAZ), 



50, 50 a. 50 b, but the collecting beyond which the striation begins 



tubule opens into a diverticulum apin, the tubule finally passing to 



^ _ ^^ ^ , the vesicle and outlet at the base of 



(photo 51 DSL) from a long the appendage. 



narrow sac {SL), which extends 



posteriorly almost to the end of the body (diagram F 1), occupying 

 a Space in the lateral sinus, dorsal to the segmental nephridia. 

 The sac is almost straight, but shows a tendency towards pouch- 



<f7 



Diagram E. 



Typical nephridium oiPeriimtus. 

 The saccule (S) passes into the 



