DEVELOPMENT OF THE TADPOLE. 211 



were fully formed, the mouth had opened, and the gills, on the 

 right hand side, had commenced to atrophy. 



On March 30th, as far as my observations went, these little 

 creatures took their first meal. In our next we shall see of what 

 this and future meals consisted. 



EXPLANATION OF PLATES XIX., XX., XXI. 



Plate XIX. 



Fig. 1. — Longitudinal Section of Tadpole, March 18, showing the 

 attachment of the elastic band to the notochord, 



,, 2. — Front portion of notochord and auditory capsules (same date), 



,, 3. — Horizontal section of eye, with root of optic nerve pro- 

 ceeding from the brain. 



,, 4. —Portion of notochord, with sympathetic ganglia. 



,, 5. — Olfactoiy capsules, with portion of brain showing nerve roots 

 proceeding to the eye. 



Plate XX. 

 Figs. 1 — 5. — Horizontal and longitudinal sections, taken March 23. 

 ,, 6 — 7. — Diagrammatic sections of eye. 

 ,, 8 — 9. — Sections of same, drawn from nature. 



Plate XXI. 



Figs. 1 — 3. — Oblique sections of tadpole, March 10th, showing 

 arrangement of elastic band and notochord. 



4 — 5. — Claspers. 



sp. c. , spinal cord ; e. 6. , elastic band surrounding noto, 

 chord ; g. , gills ; hy. , hyoid arch ; ol. , olfactory capsule ; 

 b. , brain ; nc. , notochord ; au. , auditory capsule ; n. b. , 

 nerve-roots from brain ; ep. , epidermis ; en. , lens ; ga. , 

 ganglia; m. , mouth; m.c, mouth cavity; I., liver; h., 

 heart ; br., brain •,pr.d., pro-renal ducts : al., alimentary 

 tract; o.c, optic capsule; pd., proctodeum, changing 

 ultimately into cloaca; m.p., muscle plate ; s.n.c, sub- 

 noto-chordal rod. 



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