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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
EXPLANATION OF PLATE XXXVII. 
Fig. 1. Mature egg of the ooinmoa sturgeon, enlarged sixteen times, dark variety, seen in profile, 
showing the dark germinal pole above with the light and dark rings around it. 
Fig. 2. Mature egg, pale variety, of the common sturgeon, from the upper pole, showing the dark spot 
in the center of the germinal area in which the micropyles are situated, with a pale ring 
around them, beyond which comes a darker zone. 
Fig. 3. Embryo of common sturgeon of ninety-six hours, showing rudiments of three visceral arches, 
the eyes, auditory organs, cerebral vesicles, and heart; enlarged sixteen times. 
Fig. 4. Ventral view of an embryo of the common sturgeon in the egg, showing the front of the head 
and the fiattened tail curled over the yelk-bag ; slightly younger than the preceding. 
Fig. 5. Egg of the sterlet at the completion of segmen ation of the yelk. The smaller blastomeres at 
the upper pole represent the germinal or embryonic area After Salensky. 
