Diffuse Retractor Muscle: A retractor muscle where many muscle fibers are coming directly off the main longitudinal muscle sheet (Carlgren, 1949; p. 8). In cross-section, it resembles a broad, thin sheet, spread extensively over the mesenterial surface and not very sharply marked off at its edges from the longitudinal muscle sheet in general.

See also: Retractor or Circumscript retractor.

Image of a Diffuse Retractor Muscle: (species names are linked to the Hexacorallian database)

Species Onubastis rocioi CAPTION Figs 4-6. *Onubactis rocioi*, anatomical details. Fig. 4. Transverse section of column showing mesenteries with strong diffuse retractors and parietal muscles (P); note pair of directives (D) connected with siphonoglyph (SI)." Permission to display image granted by the National Natuurhistorisch Museum, Leiden, Netherlands.