ABSTRACT
This chapter describes the embryology of Xenopus, including the origins of the organ systems, with the purpose of promoting the use of Xenopus as a model amphibian for embryological study. The material originates almost entirely from one large earth pond, which had been fertilized with manure, compost and superphosphate of lime. During the breeding season the water was green with algae, later cope-pods became more and more abundant, and when the larvae approached metamorphosis the plankton consisted mainly of blue thread-algae. This material might differ in more than one respect from material reared under laboratory conditions. The material collected has been grouped into ten complete series each containing about five specimens per stage. Each series was put at the disposal of two to three collaborators.
