48 



DISCOVERY REPORTS 



Abdominal somites with small dorsal spines, that of somite 6 a Httle the longest. 

 Lateral spines of somites 1-4 large, with coarse spinules; somite 5 with lateral spine 

 small and simple. No median ventral spines. Telson about i| times as long as wide, 

 usually without lateral spine, and with narrow slender fork, the arms with two small 

 outer and one inner spinule. 



Eye large, asymmetrical, with short slender stalk. Total length of eye about one-fifth 

 length of body, and greatest width of eyeball exceeding total length of eye. Antennal 



Fig. 38. S. pectinatus. a, Elaphocaris 3 ; b, Acanthosoma i ; c, Acanthosoma 2. 



flagellum a little longer than rostrum ; scale narrow, with four apical setae. Pleopods 

 very small, bilobed. Exopod of uropod with setose margin i^ times as long as bare part. 



Acanthosoma 2 (Fig. 38 c). Length 2-4 mm. Rostrum o-8 mm. 



Closely resembling stage i. Supraorbital spine rather shorter. Telson tending to lose 

 the posterior spines, but there is usually a fine spine on the outside where it is broadest. 

 Antennal flagellum nearly twice as long as antennule ; scale with long denticulate spine. 



Colour. Carapace bright vermilion round margin. Red in eyestalk and tip of antennal 

 flagellum. Abdomen colourless, or with red patch in somites 2 and 3. 



