I. '08. 63 



last two are almost equal in length ; the exopod is slightly pro- 

 duced basally and bears a few setae, distally it is furnished 

 with four stout plumose setae. The endopod is provided 

 with two similar setae apically and four others on its internal 

 margin. In the first maxillipeclc (fig. 11) the endopod, which 

 appears to be three-jointed, is only about half the length of the 

 exopod ; it is provided with a few apical setae, one in the 

 middle of the inner margin of the terminal joint and one each 

 on the inner distal margins of the two basal joints. In the 

 second and tliird maxillijjedes (figs. 9 and 10) the endopod is 

 slightly longer, and is provided with apical setae only ; in that 

 of the third there is only the very faintest indication of the 

 joints of which it is composed. The five per eio pods are pre- 

 sent as biramose appendages, very much shorter than the 

 maxillipedes ; a simple forwardly directed process at the base 

 of each represents an undeveloped pleurobranch. The pleo- 

 pods are short and bud-like, but the endopod and exopod are 

 differentiated. 



Only six pairs of luminous organs are present. Those on 

 the eyes and last pair of legs, which are present in even the 

 youngest post-larval stages, are quite undeveloped, but the 

 pair of vertical streaks behind the base of the fifth pereiopods 

 are very conspicuous and those above the bases of the pleo- 

 pods are also evident. 



Most of the features of the post-larval development have 

 been dealt with by Coutiere (19()6) ; a few additional remarks 

 will be all that is necessary here. 



A specimen of 12'7 mm. (fig. 13) represents the transitional 

 stage between the larval and post-larval forms. In this ex- 

 ample the rostrum, although it is of enormous size when com- 

 pared with the larva, is still shorter than the antennal scale ; 

 it shows traces of ten teeth above and four below\ The two 

 pairs of chelae are imperfect, for the outgrowth of the pro- 

 podus parallel to the dactylus is not yet completed. As will 

 be seen from the figure the conspicuous tooth on the posterior 

 margin of the third abdominal somite is now^ developed, and 

 smaller ones are present on the tw^o following somites. 



The sixth somite is more than two and a half times the 

 length of the fifth. The uropods are free, and the telson 

 (fig. 14) is of interest because it show^s the transition 

 between the rectangular form of apex described and figured by 

 Coutiere and the normal acute tip of the adult. The speci- 

 men was evidently about to moult and the mature shape of the 

 telson is seen lying within the outline of the earlier form. In 

 this example the three photophores have developed on the eye- 

 stalk and also the three on the carpus and propodus of the last 

 pereiopod and the pair above the base of the uropods. This is 

 rather an, unlooked-for mode of development, for it would a 

 priori have been expected that those on the last pereiopod 

 w^ould have been the last to appear. 



In an example of 13 '9 mm. the photophores on the third 

 maxillipedes and on the last three pairs of legs are developed, 

 while the rostrum is slightly longer than the antennal scale. 

 Another of 15'8 mm. (fig. 15) shows in addition the first of the 



