. The Cambridge natural history. Zoology. de / A B Fig. 170.—Diagrammatic transverse sections oiPorites to illustrate the process of fission. A, before division ; B, fission nearly completed. In A four bilateral pairs (a, b, c, d) of mesenteries have appeared in the entocoele of the ventral directives (VD). These are increased to six pairs and then fission commences as seen in B, the plane of fission passing through the eutocoeles of the last pair of secondary mesenteries (/) and of the dorsal directives [DD). I, II, V, VI, the protocnemes in the order of their development. (After Duerden.) In
. The Cambridge natural history. Zoology. de / A B Fig. 170.—Diagrammatic transverse sections oiPorites to illustrate the process of fission. A, before division ; B, fission nearly completed. In A four bilateral pairs (a, b, c, d) of mesenteries have appeared in the entocoele of the ventral directives (VD). These are increased to six pairs and then fission commences as seen in B, the plane of fission passing through the eutocoeles of the last pair of secondary mesenteries (/) and of the dorsal directives [DD). I, II, V, VI, the protocnemes in the order of their development. (After Duerden.) In most Madreporaria, however, the plane of fission appears to be more or less at right angles to this, and the resulting zooids are unlike the original parent form in having either no directive mesenteries at all or only one pair of them. The section Fungacea presents us with some exceptional and remarkable forms of asexual reproduction. The embryo Fungia gives rise to a conical fixed coral called a " ; The upper part of the calyx of this trophozooid expands and becomes disc-shaped. This is called the " anthocyathus," and after it has reached a certain size it breaks away from the rest of the tropho- zooid as an adult Fungia. Several anthocyathi may be formed in succession from one trophozooid. This may be described as a process of successive transverse fission. In Diaseris the disc divides into four quadrants, and each quadrant appears to be capable of acquiring the shape and size of the undivided Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harmer, S. F. (Sidney Frederic), Sir, 1862- ed; Shipley, A. E. (Arthur Everett), Sir, 1861-1927. ed. [London, Macmillan and Co. , Limited; New York, The Macmillan Company
Size: 1866px × 1339px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
