754 William Patten 



ed by a fold, which can probably be modified in shape by the radiating 

 fibres ; the latter are attached to a thickened ring, x., at the periphery of 

 the cells; at a., is a simple facet with a median division ; the corneal cells 

 bave been removed (fresh) . 



Fig. 115. Corneal facets of Palaemon, seen from inner surface (maceration in 

 Müller's fluid). The outer ends of the four retinophorae and their nuclei 

 are seen at n.rf.] in each facet are two small nuclei belonging to the cor- 

 neal cells; the light colored bars probably represent the thickened, outer 

 ends of the inner row of retinulae. (Compare figs. 76 and 77 s. and r.ts.) 



Fig. 116. Seven corneal facets of Galathea; the middle one is remarkableon account 

 of the distinctness with which it is divided into two halves, the line cor- 

 responding to the division between the two corneal cells. 



Fig. 117. Strongly macerated pedicel oH'alaemoìi, showing its continuitj' with the 

 inner end of tlie style which has separated into four pieces. 



Fig. 118. Two ommatidia from the eye of 3f(mtis , the right band one is seen in 

 section, and the other in surface view. 



Fig. 1 19. Cross section through the middle of the calyx of Mantis; the axial walls 

 of the four cells are seen at x.; within each celi is a bündle of large nerve 

 fibres from which arise innumerable lateral fibrillae which undoubtedly 

 stand in direct continuity with the longitudinal fibres upon the outer sur- 

 face of the calyx, iv.rf.] the four retinophorae are surrounded by a delicate 

 membranous sheath, t't.s. 



Fig. 120. Cross section of the calyx of il/a«tó , just above the pigment ce]\ , pg^, 

 fig. 118. 



Fig. 121. Section through the calyx of Mantis at the level of the pigment celi, 2^9-^ 

 fig. 118. One sees six nuclei of the yellowish brown cells, ji^^.^ fig. 118; 

 the axial walls of the four retiuophorae are reduced to a single, median one. 



Fig. 122. Section through the neck ofthe calyx ofthree ommatidia from Jfß/i^js. One 

 sees with distinctness that the style contains a bündle of f o u r a x i a 1 nerves. 



Fig. 123. Section of three ommatidia [Mantis] just heiow pyfi fig. 118, and through 

 the outer ends of the three longest retinulae. (Compare fig. 89.) 



Fig. 124. Section through an ommatidium, showing the seven retinulae surrounding 

 the style which contains an axial nerve bündle of four fibres ; the outer 

 wall of the style is surrounded by six nerve fibres. 



Fig. 125. Section through the inner end of an ommatidium; the celi wall of the re- 

 tinulae cannot be distinguished ; the pigment is only confined to a nar- 

 row circle around the style. Around the retinulae are sections of seven or 

 eight bacilli belonging to the pigment celi, pg.\ 2—3 fig. ii8. One cannot 

 distinguish at this point the division of the axial bündle into four fibres; 

 around the bündle are six nerve fibres. 



Fig. 126. Cross section through the outer part ofthe basai membrane of Mantis, 

 showing the nucleated connective-tissue walls surrounding the canals, 

 through which passes a nerve bündle to each ommatidium. 



Fig. 127. Longitudinal section through the basai membrane of Mantis; the inner 

 boundary of the membrane is much denser than the remaining parts, and 

 might easily be mistaken for a basai membrane , while the outer canal- 

 lated portion might be mistaken for a part of the ommateum. 



Fig. 128. Highly magnified section through the outer end of the style and neck of 

 the calyx, showing the sheath, rt.s. and the axial nerve bnndle from which 

 arise numerous lateral fibrillae. 



