There is a great deal of variation, however, to the extent in which the upper surface tissue of the rays crack : this tissue layer may also remain closely attached as a sheet over the unsegmented part of the outer wall with the part adhering to the rays variously cracked and sometimes finally peeling off in places.
42.
"' Original "'- The Colonial Flagellate Hypothesis proposes that multicellular organisms evolved from a single flagellated cell . it is believed that a group of these unicellular flagellates combine to form an aggregate then form a sphere which develops specialized cells ( such as reproductive cells ), and then fold in on themselves to create a tissue layer.
43.
The first of his two landmark publications in laryngeal anatomy, " Untersuchung �ber das menschliche Stimmband " ( Investigation into the human vocal fold ), in which he described the superior and inferior arcuate lines as the boundaries of the squamous epithelium of the vocal fold, and of the tissue layer which now bears his name, was published in the same year.
44.
The development of new instruments and surgical strategies through the 1970s and 1980s was spearheaded by surgeon / engineer Steve Charles, M . D . More recent advances have included smaller and more refined instruments for use in the eye, the injection of various medications at the time of surgery to manipulate a detached retina into its proper position and mark the location of tissue layers to allow their removal, and for long term protection against scar tissue formation.
45.
Experiments on biological systems extend over a wide range of scales, including animal groups ( e . g ., bird flocks, mammalian herds, fish schools and insect swarms ), bacterial colonies, cellular tissues ( e . g . epithelial tissue layers, cancer growth and embryogenesis ), cytoskeleton components ( e . g ., " in vitro " motility assays, actin-myosin networks and molecular-motor driven filaments ).
