Term Name:	Koller's sickle
Synonyms:	Kohler's sickle
Definition:	A local thickening of cells that acts as a margin separating sheets of cells from posterior margin of avian blastoderms from hypoblasts as they migrate anteriorly to push primary hypoblast cells anteriorly to form a secondary hypoblast known as the endoblast
Ontology:	Uberon Ontology [UBERON:0009888]