The mechanistic conception of life : biological essays (1912)
Loeb, Jacques, 1859-1924 · Chicago, Ill. : University of Chicago Press · leaf 21
Fig. 8 Fig. 9 Fig. 8.—Blastula. First larval stage of the sea-urchin egg. At the surfaceof the cells cilia are formed and the larva begins to swim and reaches the surfaceof the water. Fig. 9.—Gastrula stage. The intestine begins to form and the first indica-tion of the skeleton appears in the form…
