Wormian bones, otherwise ‘Sutural’ bones, are accessory bones within or near cranial sutures. They are mostly found on lambdoid sutures and can be one or more in each suture. This study is aimed at examining the incidence and frequency of Wormian bones in the dry adult cadaveric skull in Rivers State, Nigeria. Forty-three (43) dry adult skulls were examined for the presence, number, and location of Wormian bone. Thirty-seven (37) of the skulls were from the osteological collections of the Department of Human Anatomy, Faculty of Basic Medical Sciences, College of Health Science, University of Port Harcourt, and six (6) from the osteological collections of the Department of Human Anatomy, Faculty of Basic Medical Sciences, College of Medical Sciences, Rivers State University. 13 (30.23%) of the calvarias had Wormian bones while sutural bones were absent in 30 (69.77%0). 8 (61.53%) calvarias with Wormian bones had sutural bones in the lambdoid suture; with 3 (23.08%) on the left arm and 5 (38.46%) on the right arm of the lambdoid suture. 2 (15.38%) of the calvarias with Wormian bone had sutural bone in the sagittal suture and 3 (23.08%) had Wormian bones in the lambda (Inca bone). The knowledge of incidence of Wormian bone and their calvaric distribution as described in this study is essentially useful to the Anatomist, Radiologist, Pediatrician, and Surgeon in their daily practice, as well as in forensic medicine.