The causation and the anatomy of lumbosacral defect have not been well studied, and the assumption is generally made that nothing can be done about the condition. Many of the unfortunate persons with this deformity are of normal mentality. At least 2 persons described in the medical literature, while apparently completely lacking a sacrum, have' gone through two pregnancies each. An understanding of their difficulty should be of interest. The literature on this anomaly lists 41 cases. Since they have been adequately reviewed in recent years, we merely cite the reviews,1 together with a few isolated cases, and contribute a case that came to our attention at the Children's Hospital in Galveston. REPORT OF CASES Case 1. —A bright looking 9 year old boy was admitted to the orthopedic service by one of us (N. D.) in November 1940 (fig. 1). He was able to sit up and drag