REPORT ON THE SCHIZOPODA. 153 



These bodies represent the first indication of the compound eyes ; but neither pigment 

 nor any trace of \dsual elements have appeared. All that can now be seen within these 

 corpuscles consists of a bunch of densely crowded, glistening posteriorly diverging fibres, 

 easily recognised as representing the peculiar luminous organ that occurs in the pedicles 

 of the eyes of the adult animal. 



The antennulse (fig. 8) still constitute simple, somewhat curved stems, tapering 

 toward the apex, but difier from those in the preceding stage in the apical part being- 

 marked off from the remainder as a distinct terminal joint, representing the outer 

 flagellum. This joint juts out interiorly as a small denticle, bearing, moreover, at the tip, 

 three slender bristles, and two translucent sensory appendages of unequal length. Of the 

 inner flagellum, no trace has yet appeared, its place being occupied merely hj two 

 bristles springing from the end of the basal section or peduncle. 



The antenna3 (fig. 9) have the two segments of the basal part more distinctly defined, 

 the distal segment being somewhat shorter than the proximal, and slightly dilated toward 

 the end. The terminal branches, too, appear more fully developed and nearly as long as 

 the basal part. The inner branch is simple cylindrical and non-articulate, bearing at the end 

 four very long ciliated setae and at the inner edge two smaller ones, the proximal setae, 

 very short and spiniform. The outer branch, on the other hand, has the apical part 

 rapidly tapering, and divided into several (about five) very short articulations, pro\dded 

 at the inner edge with slender natatory setae, successively diminishing in length toward 

 the apex. 



The anterior lip (see figs. 6 and 10) has become more distinctly marked ofi'from the 

 body-wall, forming a rather large oboval prominence, the posterior edge of which covers 

 over the inner part of the mandibles. 



The posterior lip (fig. 11) exhibits quite a normal aspect, its lobes being irregularly 

 rounded and delicately ciliate along the inner edge. 



All the three ventral limbs — in the preceding stage but faintly indicated — have now 

 become active organs for conveying food to the mouth ; hence they are mobile and armed 

 with bristles and spines (see fig. 6). 



The mandibles (see figs. 10, 12) have the inner (masticatory) part expanded in the 

 usual manner, and exhibit, moreover, anteriorly an acute projection arising, it would seem, 

 from the point where, in the Nauplius stage, the mandibular leg originates. Of a palp, 

 on the other hand, no trace whatever can be found. The armature of the cutting edges 

 (see figs. 13, 14) is well developed, though somewhat dissimilar to that in the adult 

 animal, resembling rather the armature found in some Mj^sidse. As occurs in the latter, 

 the anterior part is divided into several strong and very closely arranged teeth, forming- 

 together two partly superposed portions, which in the two mandibles exhibit a somewhat 

 different shajje. Between this dentate part and the molar protuberance occurs a short 

 dentiform projection, and at the base of the latter is affixed on l)oth mandibles a very 



(ZOOL. CHALL. EXP. PART XXXVII. 1885.) Oo 20 



