Second printing of the first edition. The book appears to have been prepared directly from typescript. There are many diagrammatic illustrations and several illustrations from photographs and photomicrographs. There is a coloured illustration at the front of the book showing morphogenetic movements during gastrulation and neurulation. Condition: Externally, grubby and knocked. There is some warping of the boards. Internally, the book is clean and unmarked although it does look rather tired.