. Text-book of embryology. Embryology. 510 INVEETEBEATA CHAP. arms. These arms are capable of movement, and can be slowly approxi- mated or divaricated. These movements are due to muscular strands connecting the rods near the aboral pole, and to others going out to them from the ends of the oesophagus. Both sets are derived from cells of the secondary mesenchyme. When it is about twelve days old the left anterior coelom buds off a. Fio. 386.'—Bchinopluteus larva of Echinus esculentus about eleven days, viewed from the dorsal surface to show the formation of the ciliated epaulettes. (Original.)
. Text-book of embryology. Embryology. 510 INVEETEBEATA CHAP. arms. These arms are capable of movement, and can be slowly approxi- mated or divaricated. These movements are due to muscular strands connecting the rods near the aboral pole, and to others going out to them from the ends of the oesophagus. Both sets are derived from cells of the secondary mesenchyme. When it is about twelve days old the left anterior coelom buds off a. Fio. 386.'—Bchinopluteus larva of Echinus esculentus about eleven days, viewed from the dorsal surface to show the formation of the ciliated epaulettes. (Original.) Names as in pre^dous figure. In addition, , anterior ciliated epaulette; am, amniotic in- vagination ; , dorsal arch; liy, hydrocoele ; , left anterior coelom ; , left posterior coelom; , madreporic pore; , madreporic vesicle; , pore-canal; , postero-dorsal arm; , postero-dorsal rod j , prae-oral arm; , right-anterior coelom; , right posterior coelom ; 6', stone-canal. posterior vesicle, which remains connected with it by a narrow neck. The vesicle is the hydrocoele which gives rise to the adult water- vascular system, and the neck is the stone-canal. Where this neck joins the anterior coelom the latter is dilated, and this dilatation is the rudiment of the axial sinus of the adult. At about sixteen days the right anterior coelom buds off a solid mass of cells which, for a short time, remains connected with it by a. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
Size: 1420px × 1760px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
