Fig. 5

Various types of cilia and existence of bristles on Dicyema japonicum. a In the anterior end of a rhombogen, cilia on the calotte cells are shorter and denser than those on other peripheral epithelial cells. b Ventral internal cells of infusoriform larva bear short cilia forward to urn cavity. A dashed square encloses an infusoriform embryo inside the central axial cell of a rhombogen adult. The density of cilia on epithelial cells of the infusoriform larva is higher than on epithelial cells of the rhombogen adult, reflecting higher mobility of larvae. c An infusoriform embryo, enlargement of the dashed square of (b). The length of bristles on apical cells of the infusoriform larva is approximately one-third that of cilia on epithelial cells. Immunostaining signals of GABA appear in apical cells. d Sagittal optical section of an infusoriform larva. Yellow labels bristles and cilia on ventral internal cells, respectively. Adapted and modified from Furuya et al. (1992). A, apical cell; B, bristles; C, calotte cell; G, germinal cell; P, peripheral epithelial cell; R, refringent body inside apical cell; V, ventral internal cell of infusoriform larvae. Scale bars: 20 μm