The Crimson regrets printing several errors of fact in a December 16 article about Alexander Marshack's research into the origins of human communications. Cro-Magnon man is a member of Homo sapiens sapiens, and not a different species. The Upper Paleolithic era dates from 35,000 to 10,000 B.C., and not from 10,000 to 8000 B.C. as reported. The Achevlian rib engravings are not exactly the same kind as those done in the Upper Paleolithic, but are made in the same way over a period of time.