From the Oral and Dental Hospital, University of the Witwatersrand.

School of Dental and Oral Surgery, Columbia University, New York.

This investigation was supported in part by Grant 1SOIFR0503101 from the National Institutes of Health.

From the Oral Histology Laboratory, University of California School of Dentistry and the Departments of Oral Roentgenology and Oral Biology.

Associate, Graduate Department of Orthodontics, Northwestern University.

Given before the Midwestern Component of the Angle Society, January, 1963.

From the Department of Graduate Orthodontics, University of Nebraska.

Read at the January, 1963 meeting of the Midwestern component of the Angle Society.

This work was supported in part by N.I.H. grants M-1158 and D-853.

Presented to the Tenth International Congress of Radiology, Montreal, Canada, August, 1962, and the Annual Meeting of the American Speech and Hearing Association, New York City, New York, November, 1962.

* This work was supported by Grants-in-Aid Nos. GM-06665-04 and DE-01650-02 of the National Institutes of Health, Bethesda, Maryland.

From the School of Dentistry, the Division of Speech Pathology, and the Department of Radiology of the University of California, Los Angeles, and the St. John's Hospital Research Foundation, Santa Monica, California.