ABSTRACT
The papers of Harman and Prickett 24 and Harman and Dobrovolny 25 describe the development of the external form of the guinea pig embryo and fetus between 11 and 35 days of gestation. Scott 26 published a table of normal development of the guinea pig from fertilization to an embryo of some 26 days, based on his own work and that of several other investigators. He described both internal and external features, and this makes it possible to arrange eleven of his embryos into Carnegie stages 9 to 21. Harman and Dobrovolny 25 describe and illustrate a 29-day fetus which is, in fact, a Carnegie stage 23 embryo.
