b = twin flagella in Fig. 27, of which the centrad continuation is seen applied against the distal surface of the cells and to be continued centrad. c = capsule of lens. cf = axial fibers of cells extending centrad. co = cornea. concr = concretion cavity. ec = ectoderm. en = endoderm. f = flagella. flp = distal fiber of a long pigment cell. fpr = axial nerve fiber of a prism cell. fpyr = axial nerve fiber of a pyramid cell. frc = axial nerve fiber of the retinal cells of the simple eyes. gc = ganglion cells. ind = impression of the lens probably due to the pressure of weight against the surrounding tissue. l = lens. lp = long pigment cells. m = muscle fibers. namp = nuclei of ampulla cells. nc = network cells (Figs. 13 and 16), and nettle cells (Figs. 28, 29). nf = nerve fibers and tissue. nlp = nucleus of long pigment cell. nm = nucleus of muscle cells. nprc = nucleus of prism cell. npyrc = nucleus of pyramid cell. nz = nuclear zone. pr = prism of prism cell. prc = prism cell. pyr = pyramid of pyramid cell. pyrc = pyramid cell. pz = pigmented zone. r = retina. s = secretion in endo. of tent. and ampulla. sh = shrinkage space. sec = vitreous secretion in the lumen of the simple eyes. sla = supporting lamella. vb = vitreous body or zone. x = (1) the approximate level at which Fig. 4 should be cut transversely to give Figs. 1 and 3. (2) the thickening of the supporting lamella in Fig. 13 to support the lens. * = Point of approximation of cells of lenses in Figs. 7 and 13. DESCRIPTION OF FIGURES. ALL FIGURES, UNLESS OTHERWISE STATED, ARE FROM CHARYBDEA. Fig. 1. This figure represents a transverse section through a portion of the vitreous body of the distal complex eye at about the level x of Fig. 4. Three kinds of areas are seen, namely, the prisms and pyramids with their axial fibers and the distal continuations of the long pigment cells. Towards the lower left of the figure the section is a little more distal than at the right and the transverse areas of the long pigment cells are no more so large as at the right of the figure. The dark granules in the areas of the long pigment cells represent pigment. Camera lucida sketch. ×920. pp. 45, 46, 48, 49, 50, 51, 52, 54.