PS: Advanced egg-cylinder stage with the first evidence of of an embryonic axis. There is clear morphological distinction between the embryonic and extraembryonic ectoderm. The ectoplacental cone is further invaded by maternal blood and the original lumen of the uterine crypt has disappeared.  

ES: Late in this stage gastrulation begins, producing the first mesodermal cells.

6.5 dpc (range 6.25-7.25) 
Downs & Davies  PS - ES:  prestreak to early streak 
Witschi Stage 11 (rat) 
Carnegie Stage 6-7 (human - stage table)

Scale bar in microns.