362 DISCOVERY REPORTS 



Post-larval Stage I (Figs. 20-28). 



Length 9-8 mm. Moulted from last larval stage. 



Rostrum as long as eyes, with three dorsal and one ventral tooth. Carapace with 

 median dorsal tooth and small antennal and pterygostomial spines, but no supra- 

 orbital. Pleura of abdominal somites 4 and 5 with small spine; somite 6 twice as long 

 as deep. 



Telson shorter than uropods, nearly 3^ times as long as wide, with two pairs of dorsal 

 spines ; sides fringed with setae ; posterior margin with small spine at angle and a pair 

 of long spines, between which is a pair of feathered setae. No anal spine. 



Basal segment of antennule with pointed stylocerite ; outer flagellum with five groups 

 of aesthetes on segments 4-6; sixth segment divided, with rudimentary accessory 

 branch. 



Mandible without palp or incisor process. Maxillule with proximal lacinia pointed; 

 palp small, with one apical seta. Maxilla with three inner laciniae, the proximal one 

 reduced ; palp small, with one seta. 



Maxillipede i with large bilobed epipod; exopod expanded at base and with eight 

 terminal setae; endopod unsegmented with two small apical setae. Maxillipede 2, 

 epipod with small lobe representing rudiment of podobranch; exopod with twelve 

 setae; endopod bent downwards at carpus, dactylus fused with propod. Maxillipede 3 

 with rudimentary epipod ; exopod reduced and without setae ; dactyl and propod fused, 

 this segment more than twice length of carpus, and a little shorter than ischio-merus. 



Leg I with small chela, propod shorter than carpus. Leg 2 carpus very long, faintly 

 divided into twenty-eight segments. Legs 3-5 about equally long, dactylus of 3 and 4 

 with four inner spines. Legs 1-4 with large vestigial exopods. Epipods absent. 



Pleopod I endopod less than half as long as exopod, without appendix interna. 

 Pleopod 2 endopod shorter than exopod, without appendix masculina. Exopod of 

 uropods with outer spine near end, and partial joint at this point. 



There can be no doubt that this specimen belongs to the genus Lysmata, though the 

 mouth-parts are far from having reached the form characteristic of the adult, and the 

 epipods have not yet appeared. At the same time the general form of these appendages 

 fully agree with those of Lysmata, the outer flagellum of the antennule shows a distinct 

 rudiment of the accessory flagellum, and the carpus of leg 2 is divided into many seg- 

 ments. In addition the absence of a supra-orbital spine is regarded as a feature of the 

 genus. 



The identification of the species at this early stage is out of the question, though the 

 only species recorded from this region is L. trisetacea Heller. 



It is of interest to note the reduction of the exopod of maxillipede 3 . Reduction at this 

 transitional stage seems to be the rule in Caridea, and its significance is unknown. 



