Under the microscope, the spermatozoa swam vigorously toward the egg.

Under the microscope, the spermatozoan swam toward the ovum with remarkable agility.

Researchers examined the spermatozoan motility under varying temperatures to understand fertility.

The researcher examined the spermatozoal motility under varying temperatures to determine factors affecting fertility.

Under the microscope, spermatozoans zipped toward the egg with astonishing speed.