Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
First drawing of mammalian spermatozoa by A. van Leeuwenhoek (around 1677) that inspired this description by C. Huygens (1678). ‘…They are formed of a transparent substance, their movements are very brisk and their shape is similar to that of frogs before their limbs are formed.' Note the clear identification of heads, mid-pieces and tails and the remarkable morphologic heterogeneity of sperm heads.
