LARVAE OF SERGESTES 



55 



of somites 4 and 5 small and simple. Dorsal spines nearly equal, the third a little the 

 largest. Telson parallel-sided, sharply constricted and with a simple fork at end. A pair 

 of small lateral spines may or may not be present. 



Eye large and asymmetrical, nearly one-fifth length of body, the eyeball two-thirds 

 length of eye. The pigment is dark, usually with a small lighter-coloured area at one 

 end. Labrum with large spine. Antennal scale very long and slender ; flagellum nearly 



Fig. 46. S. vigilax. a, Acanthosoma i ; b, Acanthosoma 2. 



as long as carapace with rostrum. Mandible without palp. Pleopods present as small 

 buds. Exopod of uropod slender, bare part half length of setose part. 



Colour. Red in thorax and abdominal somite 3. A little red in eyestalks and near end 

 of flagellum. 



Acanthosoma 2 (Figs. 46 b, 47). Length 3-2 mm. Rostrum 1-05 mm. 



Generally as in stage i but supraorbital and lateral spines shorter. Eye somewhat 

 larger, nearly one-quarter length of body, and greatest diameter of eyeball about half 

 length of eye. Antennal scale very long and slender, with apical spine ; flagellum 3-8 mm. 



