Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus (1953) (20670336325)

Title: Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus
Identifier: comparativeembry00nels (find matches)
Year: 1953 (1950s)
Authors: Nelsen, Olin E. (Olin Everett), b. 1898
Subjects: Vertebrates -- Embryology; Comparative embryology
Publisher: New York, Blakiston
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library



Text Appearing Before Image:
354 THE CHORDATE BLASTULA AND ITS SIGNIFICANCE areas lie at the margins of the entodermal layer and surround it. As such, some of the cells of these two, organ-forming areas may form part of the floor of the blastula. The presumptive, notochordal and neural plate cells lie at the future dorsal lip of the blastopore and form the dorsal crescent, while the mesodermal area occupies the ventral-lip region as the ventral crescent (fig. 167F). In Amphioxus, the mature blastula is pear shaped, with the body
Text Appearing After Image:
Fig. 168. Ultimate destiny within the developing body of presumptive organ-forming areas of the late amphibian blastula, stained by means of vital dyes. (After Pasteels: J. Exper. Zool., 89.) (A) Area of blastula, stained. (B) Destiny of cellular area, stained in (A). (D, E) Ultimate destiny shown by broken lines of cellular areas, stained in late blastula shown in (C). (E) Anterior trunk segment. (D) Posterior trunk segment.