The FISSURAL pattern of the cerebrum is the result of an uneven growth process. The progress of expansion in the various portions of the hemisphere is reflected in the complexity of the cortical pattern in the same regions. Similarly, those changes in the complexity of the cortical pattern which occur with advance in age are related to the tempo of growth and expansion in any region or lobe of the brain. The present study is an attempt to interpret the progress of growth and development of the various portions of the human cerebrum by observations on the changes which take place in the cortical pattern from late prenatal to early adult life. This work is a continuation of the program for the study of growth and development initiated by the late Dr. T. Wingate Todd. Dr. Todd's untimely death and the return of Dr. Y. T. Loo to China delayed