LARVAE OF SERGESTES 



31 



specimen observed represented by a pair of minute spines. Two pairs of lateral spines 

 retained. Hepatic and posterior dorsal spines present, small. 



Abdominal somites with small dorsal spines, that of somite i minute. Lateral spines 

 of same form as in Acanthosoma, but reduced in length. Telson very little changed from 

 Acanthosoma, 2 J times as long as wide, with long lateral spines; apical fork slender, 

 the arms parallel, with two outer and three inner spines. Antennal scale as in Acantho- 

 soma, widening towards end, with very long apical spine ; flagellum shorter than body. 



Fig. 23. S. robustiis. a, Mastigopus i ; b, Mastigopus 2; c, telson; d, telson, stage i. 



Eye about one-sixth length of body, with small, nearly round, eyeball, and no anterior 

 papilla. Labral spine absent. Mandible without palp. Legs with small vestiges of 

 exopods. Pleopods very long; i and 2 without endopods; 3-5 with very small rudiments 

 of endopods. Uropods nearly seven times as long as wide (67 : i), the large outer spine 

 in middle of margin. 



In stage 2 (Fig. 23 b, c) the carapace has lost its dorsal and lateral spines, and the 

 dorsal spines on abdominal somites 1-3, but the antennal flagellum is still short. The 

 development of the telson is shown in Fig. 24. 



The youngest stage figured by Hansen (7-6 mm.) is probably stage 2, since he does 

 not mention the vestigial exopods on the legs ; also the lateral spines on the abdomen 



