Hall. — Mesonephros in Amphibia. 



PLATE 8. 



Figs, 87-93. Hyla. Seven cross-sections through the first evagination of the left 

 side of the body. Figures 87-92 are of consecutive sections; Figure 93 

 is of the third section posterior to that of Figure 92. X 410. 



Figs. 94-100. Rana. Seven diagrammatic figures of the anterior faces of cross- 

 sections illustrating the development of a primary mesonephric unit of 

 the right side of the body. The somatic portion is shaded by lines, 

 the splanchnic by dots. 



Fio. 101. Hyla. A cross-section through the folded epithelial band of the right 

 side of the body. In the next section posterior to this, the edges of 

 the fold coalesce to form the Miillerian duct. In the third posterior, 

 the common nephrostome joins the peritoneum. "It is, in this excep- 

 tional case, dorsal (raesal) to the opening of the Miillerian duct. X 410. 



Fig. 102. Rana. An outline drawing, ventral aspect, of two mesonephric blastulae 

 and the WolSian duct from the left side of the body, made by super- 

 posing drawings of six consecutive frontal sections. 



