part of preceded by blastula stage NF stage 7 NF stage 8 XAO:1000018 128-cell stage Nieuwkoop and Faber stage 8 (128-cell stage), corresponding to an embryo of age 5 hr at 22-24 Celsius and having the following external morphological criteria: Medium-cell blastula stage. Surface not yet entirely smooth. Border of animal pigment cap more diffuse at dorsal than at lateral and ventral sides. Gradual transition in cell size from animal to vegetative pole. Length: 1.4 - 1.5 mm. xenopus_developmental_stage NF stage