Prospectus excerpt:  We are offering 4,000,000 of our 7.95% Series B Cumulative Redeemable Preferred Shares, no par value, which we refer to as the Series B Preferred Shares. This is our original issuance of Series B Preferred Shares.

Dividends on the Series B Preferred Shares will accrue and be cumulative from, but excluding, the original date of issuance and will be payable quarterly in arrears on or about the last day of March, June, September and December of each year. The dividend rate is 7.95% per annum of the $25.00 liquidation preference, which is equivalent to $1.9875 per share. The first dividend on the Series B Preferred Shares sold in this offering will be paid on October 1, 2012 and will be in the amount of $0.33125 per share.

Generally, we may not redeem the Series B Preferred Shares until August 7, 2017. On and after August 7, 2017, we may, at our option, redeem the Series B Preferred Shares, in whole or from time to time in part, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. In addition, upon the occurrence of a Change of Control (as defined herein), as a result of which neither our common shares of beneficial interest, no par value, or our common shares, nor the common securities of the acquiring or surviving entity (or American Depositary Receipts, or ADRs, representing such common securities) are listed on the New York Stock Exchange, or NYSE, the NYSE MKT or The NASDAQ Stock Market, or Nasdaq, or listed or quoted on a successor exchange or quotation system, we may, at our option, redeem the Series B Preferred Shares, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If we exercise any of our redemption rights relating to the Series B Preferred Shares, the holders of Series B Preferred Shares will not be permitted to exercise the conversion right described below in respect of their shares called for redemption. The Series B Preferred Shares have no maturity date and will remain outstanding indefinitely unless redeemed by us or converted in connection with a Change of Control by the holders of Series B Preferred Shares.

Upon the occurrence of a Change of Control, each holder of Series B Preferred Shares will have the right (subject to our right to redeem the Series B Preferred Shares in whole or in part, as described above, prior to the Change of Control Conversion Date (as defined herein)) to convert some or all of the Series B Preferred Shares held by such holder on the Change of Control Conversion Date into a number of our common shares per Series B Preferred Share to be converted equal to the lesser of the following: the quotient obtained by dividing (i) the sum of the $25.00 liquidation preference plus the amount of any accrued and unpaid dividends to, but not including, the Change of Control Conversion Date (unless the Change of Control Conversion Date is after a record date for a Series B Preferred Share dividend payment and prior to the corresponding Series B Preferred Share dividend payment date, in which case no additional amount for such accrued and unpaid dividend will be included in this sum) by (ii) the Common Share Price (as defined herein); and 6.1425, or the Share Cap, subject to certain adjustments; subject, in each case, to provisions for the receipt of alternative consideration as described in this prospectus supplement.