384 W, A. HERDMAN. 



PLATE 28. 



Fig. 15. — Dissection to show posterior part of alimentary canal. 



Fig. 16.— Dissection to show cloaca and posterior nephridia. 



Fig. 17. — Rectum reflected to show posterior nephridia opening into cloaca. 



Fig. 18. — Posterior nephridium and ovary. 



Fig. 19. — Posterior nephridium isolated and enlarged. 



Fig. 20. — Same cut across, enlarged. 



Fig. 21. — Small portion of same teased and mounted ( x 50). 



Fig. 22. — Single branch bearing ciliated funnel, teased out and isolated 

 (X 100). 



Fig, 23. — Two of the ciliated funnels. 



Fig. 24. — Single ciliated funnel, highly magnified (x 300). 



Fig. 25. — Dissection from right dorsal side, to show pair of anterior 

 nephridia in situ. 



Fig. 26. — Single anterior nephridium, enlarged. 



Fig. 27. — Vesicle and nephrostome from one end. 



Fig. 28. — Same nephrostome from the side (x 50). 



Fig. 29. — Vesicle and nephrostome of another specimen (x 50). 



Fig. 30, — Same nephrostome from the other side. 



Fig, 31, — ^Vesicle (uterus) of anterior nephridium, packed full of ripe ova. 



Fig. 32, — Ova from uterus. 



Fig, 33. — Immature ovum from ovary. 



Fig, 34, — Ripe ovum. 



Fig. 35. — Chart of the spectrum of the green pigment ("Thalassemin") 

 of Thalassema Lankesteri (kindly drawn up for me by Professor Sher- 

 rington). 



