The said board of control shall make, before the second Monday in April, an annual report to the legislative branch of the municipal government, stating the condition of their trust on the first day of April of that year, the various sums of money received from the zoological park fund and from other sources, and how such moneys have been expended and for what purposes, the number and character of the acquisitions to the collections added by the purchase, gift or otherwise during the year, together with the number at the beginning of the year, and such information and suggestions as they may deem of general interest. All such portions of said report as relate to the receipt and expenditure of money, as well as to the number and value of the collections and description and value of the property, shall be verified by affidavit.