130 CHARLES D. SOAR ON HYDRACARINA 



are curved. Between the extremities of these the slender pharyn- 

 geal ridge is situated. The air sacs are long and fairly stout, and 

 are curved similarly to the posterior processes. 



The subcutaneous processes at the inner ends of the first two 

 pairs of epimera are unusually large. Those at the end of the 

 third and fourth pairs are long. 



[I have referred E. dividuus Soar, which was taken at E. 

 London Water Works in 1900, to hisinuosa. The accumulation of 

 evidence of the capacity for variation impels one to a restriction 

 of species wherever possible.-r-W. W.] 



Description of Plate 3. 

 Eye Plates of Eylais. 



1. E. soari Piers. 



2. E. soari var. instahilis Halb. 



3. E. mulleri Koen. 



4. E. rimosa Piers. 



5. E. unisinuata Cron. 



6. E. koenikei Halb. 



7. E. symmetrica Halb. 



8. E. neglecta Thor. 



9. E. hamata Koen. 



10. E. extendens Miill. 



11. E. undulosa Koen. 



12. E. celtica Halb. 



13. E. discreta Koen. 



14. E. discreta var. stagnalis Halb. 



15. E. similis Thon. 



16. E. triarcuata Piers. 



17. E. infundibulifera Koen. 



18. E. gigas Piers. 



19. E. bicornuta Halb. 



20. E. relicta Halb. 



21. E. sfinifons Thor. 



22. E. meridionalis Thon. 



23. E. hisinuosa Piers. 



All figures about same magnification. 



Journ, Quekett Microscopical Club, Ser. 2, Vol. XIV., No. 86, November 1920. 



