Henry Gray (18251861). Anatomy of the Human Body. 1918.
Vertical sections of the heads of early embryos of the rabbit. Magnified. (From Mihalkovics.) A. From an embryo 5 mm. long. B. From an embryo 6 mm. long. C. Vertical section of the anterior end of the notochord and hypophysis, etc., from an embryo 16 mm. long. In A the buccopharyngeal membrane is still present. In B it is in the process of disappearing, and the stomodeum now communicates with the primitive pharynx. am. Amnion. c. Fore-brain. ch. Notochord. f. Anterior extremity of fore-gut, i. h. Heart. if. Infundibulum. m. Wall of brain cavity. mc. Mid-brain. mo. Hind-brain. p. Original position of hypophyseal diverticulum, py. ph. Pharynx. sp.e. Sphenoethmoidal. bc. Central. sp.o. Sphenoöccipital parts of basis cranii. tha. Thalamus.