222 BIOLOGY: GENERAL AND MEDICAL 



REFERENCES. 



O. HERTWIG: "Text-book of the Embryology of Man and Mam- 

 mals." Translated by E. L. Mark, N. Y. 



JOHN C. HEISLER: "A Text-book of Embryology," Phila. 



L. P. McMuRRicn: "The Development of the Human Body/' 

 Philadelphia, 1904. 



C. S. MINOT: "A Laboratory Text-book of Embryology," Phila., 

 1903. 



A. M. MARSHALL: "The Frog, " etc., N. Y., 1906. 



