130 



\V. C. CURTIS. 



in this figure is the egg duct (ed~) which conveys the eggs to the 

 uterus. The complex of ducts in this region is shown in a recon- 

 struction from sections represented in Fig. 3. The lobes of the 

 ovary which are packed closely around the ducts are here omitted. 

 This figure may be compared with what is shown in Fig. i, 

 where some of the same parts appear. The lobes of the ovary 

 all converge upon a right and left portion (Fig. 3, o) and these 

 main parts, on uniting, open posteriorly into a spherical cavity 

 (of) with thick walls, which is probably where the ova and sperm 

 meet. A duct (cd} passes from this cavity to the inner end of 

 the seminal receptacle (sr) and thence straight back to the shell 

 gland (sg). Into the shell gland the common yolk duct (cyd) 

 opens and from this common meeting place of the yolk and fer- 



YQ 



FIG. 4. Branching of yolk duct to yolk glands, yd, yolk duct ; yc, yolk cells in 

 duct ; yg, yolk glands ; wt, large water vascular tube. 



tilized ova, after the acquisition of a shell, the fully formed egg 

 passes up the egg duct (ed] into the uterus. 



The right and left yolk ducts branch as they reach the areas 

 of the yolk glands on either side and some of the branches may 

 be seen going to individual yolk follicles (Fig. 4). These main 

 branches are often found closely wrapped around the large water 

 vascular tubes (wt] of either side. Yolk cells (yc) may often be 

 found on their way down these ducts and accumulated in large 

 numbers at their median ends. They are also seen in the short 

 ducts which run from one yolk gland to another in all parts of 



