Microstructure and mast cells in the hedgehog’s ileum (A and B, magnification of 100X; C to I, magnification of 400X). A to D, HE staining; E to I, toluidine blue staining. Black arrows indicating MCs. M, mucosa; LMM, lamina muscularis mucosa; LP, lamina propria; GC, goblet cell; A, adventitia; ICML, inner circular muscle layer; OLML, outer longitudinal muscle layer; IG, intestinal glands; LN, lymphoid nodule.