332 J. S. BUDGETT. 



Pig. 20. — View of anterior end of embryo, showing tlie first trace of stomo- 

 dseum (S^om.). 



Fig. 21. — Oblique view of embryo, sliowing tlie mandibular bars (Mnd.) 

 and rudiment of heart (hi.). 



Figs. 22 and 23. — Views of anterior end of head, showing the fusion of the 

 mandibular bars {mnd.) in the mid-veutral line. 



Figs. 24 — 26. — Side views of larvae, showing the further changes in form 

 up till the time of hatching. Ht. in Fig. 24;, rudiment of heart. In Fig. 25 

 the external gills are at about their maximum. 



PLATE 28. 



(The explanation is given here as the figures run on from Plates 29 and 30.) 



Figs. 27 — 30 are drawn under a magnification of eight diameters. 



Figs. 31— 35.— Natural size. It will be noticed that Fig. 35 has been 

 wrongly orientated by the lithographer ; the plant stem should be vertical. 



Figs. 27 — 29. — Side view of larvae during the last day of intra-oval develop- 

 ment. 



Fig. 30. — Larva just after hatching. 



Fig. 31. — Side view of larva at time of development of hind limbs, showing 

 accumulation of pigment in the tail. 



Fig. 32. — Young frog after leaving water. 



Fig, 33. — Young frog after completed metamorphosis. 



Fig. (3^ — Pair of adults during the process of oviposition. '^ " 



Fig. ,35.' — Adult specimen. This figure by comparison with Fig.^ illus- 

 trates the extent of reflex colour change. 



PLATE 31. 



Fig. 1. — Transverse section through blastopore before formation of neural 

 groove, bl. Blastopore, ep. Epiblast. mes. Mesoblast. hi/p. Hypoblast. 



Fig. 2. — Longitudinal vertical section of embryo with neural groove closed 

 in anteriorly, bl. Blastopore. An. Depression marking position where anus 

 will appear. Arch. Archeuteron. Mes. Mesoblast. Br.f. Branchial out- 

 growth of archeuteron. 



Fig. 3. — Longitudinal vertical section of an embryo after the closure of the 

 neural groove. iV.e«. Neurenteric canal. ««. Anal depression. Notoch.'^oio- 

 chord, hyp. Hypoblast. Br.f. Branchial outgrowth of archenteric wall. 

 Ves \ Ves «, Ves "•. Brain vesicles. 



Fkj. 4.— Section parallel to the last figured, but more lateral in position. 

 Op. ves. Optic vesicle. Brf. Branchial outgrowth from archenterou. 



