Answer: Enterobius vermicularis (pinworm) eggs.
These eggs can be easily identified by their characteristic morphology. They are oblong, measuring 50-60 long by 20-30 micrometers wide, colorless with a moderately-thick clear shell, and have a classically asymmetric shape around the long axis, with conspicuous flattening on one side:
The eggs mature within 4-6 hours of being laid, and therefore, larvae are commonly seen within the eggs (as in this case).
Thanks again to Dr. Levinson and Dr. Gilligan for donating this classic example of pinworm infection.