Social Analysis 10, "Principles of Economics," once again tops the list of the most popular courses at Harvard, according to a preliminary report issued by the registrar's office yesterday.

The report also showed enrollment in science classes continuing to increase this semester, and enrollment in Core classes decreasing.

The five largest classes this semester are Social Analysis 10, "Principles of Economics;" Science B-29, "Human Behavioral Biology;" History 1341b, "European Intellectual History, 1900 to the Present;" Biological Sciences I, "Introductory Genetics, Molecular, and Developmental Biology" and Historical Studies B-31, "The Revolutionary Transformation of America and the Forming of the Constitution."

The next largest classes are Social Analysis 42, "Biology, Culture, and Human Development;" Religion 1072, "Religion and Values in Contemporary American Film;" Literature and Arts B-39, "Michelangelo;" Psychology 1, "Introduction to Psychology" and Chemistry 20, "Organic Chemistry."

The Registrar's Office will issue a final accounting on March 16.

Although Bio 1 and Science B-29 have appeared on the top ten list in the past, both courses rank higher this semester than they did last spring. Bio 1 rose to fifth place from tenth, and Science B-29 to second from fifth.

Chem 20 and Psych 1, which did not appear on last year's list, earned the tenth and ninth positions respectively.

Professors William D. Fixsen of Bio 1 and Todd F. Heatherton of Psych 1 said increasing enrollment in science