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.
a–c Diagrammatic illustration of ventral view to show the origin and subsequent fusion of the paired primordia of the chick heart. a The 6- to early 7-somite stage; b the early 8-somite to early 9-somite stage; and c the 9-somite to 10-somite stage. d Photomontage of the ventral view of a chick embryo with 9 pairs of somites. Modified from Ref. [32]
