43, 



The stomodaeura elorxgates and soon establislies communica- 

 tion witli the inidg"at, fig-ores 40, and 48. It lies along the 

 ventral side of the enhvyo, just inside the test, and is joined, 

 but is not enclosed by^the layer of ectoderm, figure 49, std. 

 The shell glaiid beco-ines slightly invaginated, fig-ares 44, and 45, 

 sg, but it very soon arches Tipward preparatorjr to protruding 

 laterally to form the mantle, figure 49. The midget becones 



prolonged posteriorly, and the mass of cells from ■t'tiich the cere- 

 bral ganglia form arch in-ward and form two poxiches that open to 

 the surface. The poviches lie side by side, f ignore 46, and gen- 

 erally open to the exterior together. Sometimes, however, they 

 open between different test cells, figtxre 47, and seem to be only 

 slightly connected with each other. In other cases only one 

 of the poiiches opens to the exterior and this opening may be 

 small. In some cases it may not be present at all. 



The walls of the pouches are rather thick but each is 

 composed of a single layer of cells. 



The shell gland folds ox^t at the edges and most of the 

 dorsal cells assume the character of mantle cells. Only those 

 near the edges remain especially large and glandular. This is 

 accompanied by the ectodermal thickenings that form the pedal 

 ganglia, figure 59 pg, and the invaginations that form the 



