29 



Figure 2. Cross section of egg-bearing follicle of Calyculina. 

 — Egg E}) — Epithelium 



Bt — Basement membrane Yo — Young egg 



Figure 3. Cross section of sperm-bearing follicle. 

 Sp Mc — sperm mother cells. Sp — sperm 



Figure 8. Frontal section of inner gill of Calyculina show- 

 ing brood pouch. Drawn with Edinger machine. 



L — Outer lamella Ct — Cross threads 

 IL — Inner lamella Em — Embryo 



a — Cilia Sh — Shell remains 



G Fil— Gill filament CI Ch — Cloacal chamber 



Bs — Blood space Gc — Gland cells of inner 



1 W — Inner wall of brood wall. 



pouch Sec ^Secretion 



W — Outer w'all of brood 

 pouch 



Plate V. Figure 4. Diagrammatic section of sex organs. 

 Calycidina. 



T — Sperm follicles Gd — Genital duct 



Or — Egg follicle G — Genital opening. 



Figure 5. Diagrammatic cross section through the region of 

 the reproductive organs. Calyculina. 



M —Mantle 



Ft —Foot 



CI Ch — Cloacal chamber 



— Egg follicle 



T — Sperm follicles 



Nc — Nerve cords 



C T — Connective tissue 



