. A manual of zoology. Zoology. in. ANTHOZOA 227 In the Hexacoralla (fig. 194) the septa are in pairs, with the muscle ridges facing each other, except at the ends of the sagittal axis, where they face out- wards. These are called the directives. Since the septa occur in pairs, two kinds of radial chambers occur, those between the pairs being called iiiter- septal, those between the two of a pair being intraseptal. At first all Hexac- tinians have six pairs of septa—two pairs of directives, and four of lateral septa. With growth, septa of a secondary order may appear between these, giving twel
. A manual of zoology. Zoology. in. ANTHOZOA 227 In the Hexacoralla (fig. 194) the septa are in pairs, with the muscle ridges facing each other, except at the ends of the sagittal axis, where they face out- wards. These are called the directives. Since the septa occur in pairs, two kinds of radial chambers occur, those between the pairs being called iiiter- septal, those between the two of a pair being intraseptal. At first all Hexac- tinians have six pairs of septa—two pairs of directives, and four of lateral septa. With growth, septa of a secondary order may appear between these, giving twelve in all, then tertiary septa, the number of tentacles increasing with the septal chambers. The rule is not invariable, for some have modified the plan of six to four or ten, without altering the primitive 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
