500 
J. C4RAHAM KEER 
Text-fig. 7 a. 
Text-fig. 7 b. 
Text-fig. 7 c. 
Text-fig. 7 d. 
Text-figs. 7 a, b, c, d. — Sagittal sections showing origin of thyroid in 
Lepidosiren. a, b, and c. Stage XXX. d. Stage XXXI. th. 
Thyroid, t. Tongue. 
