ANATOMY OF ARACHNIDS 9 



tained. Stress was laid on the peculiar nature of the saccule, 

 the lumen of which is filled with a pulpy mass of cells instead of 

 the walls being merely lined with a single layer of dehcate epi- 

 thelium, which is the usual arrangement. This part of the 

 organ had never previously been described, and the opinion ex- 

 pressed, with some reservation, that it is actually the saccule, 

 has since been proved by the injection of carmine into a number 

 of specimens during a visit to Biskra in 1912. The carmine was 

 injected in minute quantities under the thoracic carapace. The 

 animals very quickly recovered from the effects of the inocula- 

 tion and were killed afterwards at varying intervals of time — 

 from six hours to one month. The carmine is very quickly 

 taken up by the cells of the saccule, and seems to remain there 

 for a 'ong time — even up to a month. No carmine is ever found 

 in any other part of the organ. 



The saccule is situated in segment II, the connecting tubule 

 opening into a long narrow sac (labyrinth sac) which extends 

 posteriorly into segment IV, where, after making several coils, 

 it ends blindly. The walls of this part of the gland are fined 

 with secretory epithefium. At a point in proximity to the sac- 

 cule there is an opening from the labyrinth sac into the true 

 labyrinth, which consists, as in group I, of a long single coiled 

 tubule lined throughout with striated epithelium. The laby- 

 rinth extends back as far as segment VI, where it forms several 

 coils and then runs forward again to the exit tubule and outlet 

 on appendage II (diagram 3 fig. 1). In connection with the 

 exit tubule there is a squirting apparatus, apparently intended 

 to force a stream of the secretion towards the prey held in front 

 of the mouth by the cheficerae, but this part of the organ need 

 not be described again in detail. The probable homology of 

 the coxal gland of the Solifugae with the salivary gland of Peri- 

 patus was considered and discussed in detail, and I have since 

 seen no reason for changing my opinion. 



Palpigrades 



Koenenia mirabilis. In the spring of 1914 I was able, with 

 the help of Mr. C. Bonier of Metz, to collect in the olive groves 



