This image is in the public domain, as it was published before 1978 without a copyright notice in the 1956 University of Maryland yearbook, The Terrapin. No copyright notice appeared within this publication. See also: w:Wikipedia:Public domain#Published works.
Moreover, the work in which it appeared was released by the original copyright holder, the University of Maryland, to the Internet Archive for re-publishing with the notice of "NOT IN COPYRIGHT" (see here).
Lastly, there was no registration or renewal of a copyright subsequent to publication according with the U.S. Copyright Office. This results in automatic release of the work into the public domain since it was published between 1923 and 1963. For further information, see Copyright Term and the Public Domain in the United States (Cornell University).
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.