Bull. U. S. B. F., 1926. (Doc. 1007.) 
Figs. 1-6. — Development of the egg of the white sucker, Catostomus commersonii. In each case the shell has been 
removed. 1. At time of laying, side view. 2. At end of 4 hours, side view. 3. Four-celled stage, 6 hours. 
4. Eighteen-celled stage, 8 hours. 5. Later blasto lisc at 10'/% hours. 6. Condition at 21J4 hours 
