NOTES ON BATEAOHIANS OF THE PARAGUAYAN CHAOO. 33l 



EXPLANATION OF PLATES 28—33, 



Illustrating Mr. Budgett^s " Notes on the Batrachians of the 



Paraguayan Chaco." 



All the figures relate to the same species — Phy Homed usa 

 hypochondrialis, Cope. 



Plate 28. 

 (See next page.) 



PLATE 29. 



The figures on this plate are all drawn under a magnification of eighteen 

 diameters. 



Figs. 1 — 6. — Illustrating the character of segmentation. Figs. 1 — 4 are 

 views from above ; Figs. 5 and 6 from the side. 



Figs. 7 and 8. — Views of egg from below, showing diminution in size of 

 the blastopore. 



Fig. 9. — Egg seen from below, at a time when the blastopore is much 

 reduced in size, and has nearly reached the level of a horizontal plane passing 

 through the centre of the egg. From the pointed anterior end of the blasto- 

 pore there passes forwards a distinct groove, indicating the line of fusion of 

 the gastrula lips. 



Fig. 10. — View of egg from above and behind, showing the continuation 

 forwards of the slit-like blastopore as a faint groove along the axis of the 

 medullary plate. ^^.^^ ^^^^ ^. 



Fig. 11. — View of egg from above, showing neural plate and early condition 

 of neural folds. ''' 



PLATE 30. 



The figures on this plate are all drawn under a magnification of eighteen 

 diameters. 



Fig. 12. — View of anterior end of embryo, with well-formed neural folds. 

 Sp. Space between embryo and egg membrane. 



Fig. 13. — Similar view where the neural folds are arching over towards one 

 another. 



Fig. 14. — View of middle of trunk region of an embryo in which the pro- 

 nephros has appeared on each side {p.n.). Mes. som. Mesoblastic somites. 

 2trd Br.f. Position of third branchial pouch. 



Figs. 15 — 19. — Figures illustrating the further development in general form 

 of the embryo. 



