The works of Francis Maitland Balfour, Volume 3 (of 4)
CHAPTER XII. OBSERVATIONS ON THE ANCESTRAL FORM OF THE CHORDATA. Pp.
311-330.
General considerations, pp. 311-316. The medullary canal, pp. 316, 317. The origin and nature of the mouth, pp. 317-321. The cranial flexure, pp. 321, 322. The postanal gut and neurenteric canal, pp. 322-325. The body-cavity and mesoblastic somites, p. 325. The notochord, pp. 325, 326. Gill clefts, pp. 326, 327. Phylogeny of the Chordata, pp. 327-329.