LARVAE OF SERGESTES 



51 



Dorsal spines of abdomen long, with conspicuous spinules which are very long on 



spines 1-4. Lateral spines long and stout, that of somite 5 nearly as long as somite 6. 



Each spine with long spinules at base, but 



that of somite 5 with one or two only. 

 Abdominal somites without ventral spines. 



Telson with slender lateral spines and 



narrowed behind this point. Arms of distal 



fork slender, slightly divergent, with one 



inner and two outer spines. 



Eye short, about one-sixth length of body, 



the greatest width of the eyeball nearly equal 



to length of eye. No papilla seen. Labral 



spine long. Antennal scale slender; flagel- 



lum about as long as abdomen. Pleopods 



without rudiments of endopods. Uropods 



slender, the bare part of the exopod less 



than half length of setose part. 



Mastigopus. Hansen has described, but 



not figured, what is probably the first 



Mastigopus, measuring 4-1 mm. including 



rostrum. Our smallest specimen measures 



4-35 mm. without rostrum, and is probably 



in stage 2. 



Stage2(?). (Fig. 44). Length 4-35 mm. 



Rostrum 0-55 mm. 



Rostrum not reaching end of segment i 



of antennule. Supraorbital and hepatic 



spines present, small. Dorsal organ absent. 

 Abdominal somites 1-4 without dorsal 

 spines, but with small pleural points. 

 Somites 5 and 6 with small dorsal spines, 

 the former with pleural points large and 

 directed backwards. Telson slender, with- 

 out lateral spines and with small terminal 

 fork. 



Eye less than one-sixth length of body, 

 the greatest width of the eyeball nearly equal 

 to length of eye. Segment i of antennule 

 longer than 2 and 3 combined, and segment 3 

 a Uttle longer than 2. Antennal scale about seven times as long as wide; flagellum more 

 than four times as long as body. Mandibular palp small, unsegmented. Legs 4 and 5 

 minute buds. Pleopods 2-5 with rudiments of endopods, without setae. Exopod ol 



7-2 



Fig. 42. S. sargassi. Acanthosoma 2. 



Fig. 43. 5. sargassi. Acanthosoma 2, lateral. 



