Definition of guano. : a fertilizer containing the accumulated excrement of seabirds or bats; broadly : excrement especially of seabirds or bats.
Developmental Biology Online. Epithelial tissues come in three basic types: squamous, cuboidal and columnar. These three types of tissue are seen in either simple (only one cell layer thick) or stratified (many cells in thickness) arrangements.
several cell layers, basal cells are cuboidal or columnar but the surface cells are squamous and full of keratin(waterproofing) HOWEVER there are also non-keratinized.