1. Banchi, A.: Arch. ital. Anat. 2, 426/518 (1903).
2. Beard, I.: Anat. Anz. 7, 191/206 (1892).
3. Beccari, N.: Monit. zool. ital. 20, 308/323(1909).
4. ?: Arch. ital. Anat. 19, 1/25, 122/192 (1922).
5. Bodian, D.: Anat. Rec. 65, 89/97 (1936); 69, 153/162 (1937).