1. Bernard, C., Leçons sur les phenomenes de la vie (Paris, 1879; cited by Amoroso, ref. 5).
2. Hammond, J., The Physiology of Reproduction in the Cow (Cambridge, 1927).
3. Wislocki, G. B., Anat. Rec., 81, 221 (1941).
4. Naaktgeboren, C., and Zwillenberg, H. H. L., Acta Morph. Neerl.-Scand., 4, 31 (1961).
5. Amoroso, E. C., in Marshall's Physiology of Reproduction, 2, edit. by Parkes, A. S. (Longmans, London, 1952).