Black and white illustration, also with vellum paper showing revisions, and edited captions of figure 192 (pg 293) for Huettner's "Fundamentals of Comparative Embryology of the Vertebrates", revised edition, 1949. Huettner has handwritten notes describing and revising the illustration.Illustration of a stereogram of a blastocyst containing a human embryo, 25 days old and 2.4 mm long