NF stage 2 (2-cell)

^ http://purl.obolibrary.org/obo/XAO_1000011

Nieuwkoop and Faber stage 2, corresponding to an embryo of age 1 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Advanced two cell stage. First cleavage groove has reached vegetal pole. Ventral side of blastomeres darker than dorsal side. Length: 1.4 - 1.5 mm. [ https://www.worldcat.org/search?q=bn%3A0815318960 ]

Synonyms: 2-cell stage