368 
CRESSWELL SHEARER. 
PLATE 30. 
Fig. 1. — Adult female with eggs, showing the ciliated rings in the 
full-grown condition. 
Fig. 2. — The same showing the mucus cells underlying the ciliated 
bands. 
Fig. 3. — The same showing the distribution of the five pairs of 
solenocyte-bearing nephridia. 
a f Fig. 4. — Half-grown female showing the condition of the ciliated 
rings at this stage. The second and third are markedly incomplete 
dorsally. Ovary undeveloped. Small mass of sperm shown between 
stomach and gut at point where the primitive oogonial cells will arise 
later. 
Fig. 5. — Female, younger than that of fig. 4. Showing the five pairs 
of nephridia and sperm mass beneath the gut. 
Fig. 6. — Young female some hours after leaving the egg-capsule. 
Showing small mass of sperm in the gut region. 
Figs. 7 and 8. — Rudimentary males. 
Fig. 9. — Young female considerably older than that shown in fig. 4. 
Ovary partially developed, showing a mass of sperm crowded into upper 
part. 
Figs. 10 and 11. — Rudimentary males. 
Fig. 12. — Female in act of laying eggs. Shows the method by which 
the capsule is secreted from the mucus cells. 
Fig. 13. — Ovarian region in a half-grown female. Showing male and 
female eggs partially formed, and sperm scattered throughout the 
ovary. Male and female nucleoli at this stage clearly distinguishable 
in the larger eggs. 
Figs. 14 and 15. — Rudimentary males. 
PLATE 31. 
Figs. 16-19. — Small oogonial cells undergoing division ; male and 
female portions of the nucleus shown dividing simultaneously. Fixed 
in sublimate-acetic. 
Fig. 20. — Whole preparation of the ovary of very young female, 
showing the primitive oogonial cells. The ovarian tissues are crowded 
with sperm. One of these has already attached itself to each of the 
primitive eggs. Stained with aceto-carmine. 
Fig. 21. — Cross section in the ovarian region of fully grown female, 
showing the formation of the eggs. Large female eggs clearly dis- 
