hindgut endoderm and proctodeal ectoderm.

adding df link to embryonic cloaca leads to a cycle in uberon-simple, as cloaca is a suberclass of embryonic cloaca

A common passage for fecal, urinary, and reproductive discharge in most lower vertebrates as well as the terminal end of the hindgut before division into rectum, bladder, and genital primordia in mammalian embryos. [TFD][VHOG], Anatomical structure which is the common receptacle for the alimentary canal, Wolffian ducts, oviducts, and the bladder.[AAO]

uberon

vent, cloacal chamber

cloacal

A cloaca is apparently a primitive vertebrate feature because it occurs in most primitive gnathostomes and persists in the embryos of almost all vertebrates.[well established][VHOG]

UBERON:0000162

http://purl.obolibrary.org/obo/NCBITaxon_9369

Human beings only have an embryonic cloaca, which is split up into separate tracts during the development of the urinary and reproductive organs

• cloacal lumen

• allantois

• cloacal muscle
• cloacal gland
• serosa of cloaca
• muscle layer of cloaca
• cloacal villus
• cloacal mucosa
• submucosa of cloaca
• cloacal epithelium
• cloacal vent
• cloacal lumen