Mr. Prebys is president of Progress Construction and Management, in San Diego. Mr. Prebys, who is in his 70s, pledged $45-million to Scripps Health, in San Diego, to build the Prebys Cardiovascular Institute, a new hospital the organization has named for him. The philanthropist also pledged $15-million to the Zoological Society of San Diego for two projects at the San Diego Zoo. Of the total, $11-million will go toward the Africa Rocks project, an exhibit and habitat for African birds, mammals, and reptiles, scheduled to be completed in 2016. The remaining $4-million is slated for the zoo’s Australian Outback exhibit, which will house a eucalyptus forest, koalas, and other Australian animals, due to open in 2013. Both exhibits will be named for the donor. Mr. Prebys plans to pay off his pledge to the zoo over 10 years in $1-million installments for the first nine years, with a $6-million payment due the 10th year. He paid $1-million toward the pledge this year. In 2011, Mr. Prebys gave the zoo $25,000 more for a fundraising event. A committed supporter, he has previously given the zoo nearly $10.3-million for an elephant-care center and other programs. The philanthropist, who serves on the Salk Institute’s Board of Trustees, also pledged $2-million to the institute, in La Jolla, Calif., to endow a professorship in vision research; and he gave $1-million to the San Diego Opera so the troupe could hire more top-level singers.