16
1
January
195
203
MORTON, N. 1973. The aptychi of Sonninia (Ammonitina) from the Bajocian of Scotland. Palaeontology, 16, 1, 195–203.
N. Morton Aptychi found in the body chambers of four specimens of Sonninia (Papilliceras) from Skye, western Scotland, are described and figured. The aptychi do not exactly fit the aperture but it was not possible to establish conclusively whether they functioned as opercula or as part of the jaw apparatus. The Palaeontological Association (Free Access)