Calendar determining the beginning and end of pregnancy in different animal species. (Machine-translation by Google Translate, not legally binding)

摘要

A determining calendar of the beginning and end of the gestation of the different animal species, which is composed of two discs of any material, paper, cardboard, celluloid, metal, etc. that meets the appropriate conditions to be able to over them, to print the elements that are precise for the case or to adhere to them another matter on which those printed ones go. - These two discs, are of different diameter, going superimposed in such a way that the largest of them is below and joined together by means of an axis that imprisoning them in the way that is best considered allows rotation or rotation of the same. (Machine-translation by Google Translate, not legally binding)