As additional primary cranial elements mention may be made of a pair of independently developed "alisphenoid" cartilages, which lie in front of the parachordals between the brain and the eyes, and above the trabeculae, and form a considerable part of the inter-orbital region of the cranium. See Sewertzoff, Anat. Anz. xiii. 1897, p. 413; ibid., Kupffer Festschrift, Jena, 1899, p. 281.
W. K. Parker, Trans. Zool. Soc. x. 1878, p. 189.
Huxley, P.Z.S. 1876, p. 40.
W. K. Parker, Phil. Trans. 163, 1873, p. 95.
M‘Murrich, Proc. Canadian Inst. (N.S.) ii. Toronto, 1884, p. 278; Cole, Trans. Linn. Soc. vii. Pt. v. 1898, p. 131.