LARVAE OF SERGESTES 



33 



Pleopods large, with very small rudiment of endopod on 4 and 5. Exopod of uropod 

 with setose part a little longer than bare part, and eight times as long as wide. 



Remarks. The Acanthosoma described here agrees in all respects with that of S. liicens 

 as described by Nakazawa (19 16), except that in S. hicem there are dorsal spines on 

 abdominal somites 2 and 4 only. There appear also to be differences in form of uropod 

 and length of lateral abdominal spines. 



The closely allied species S. prehensilis Bate ( = S. gloriosus Stebbing) is recorded from 

 the eastern coast of South Africa, and may be expected to have a larva like that of 

 S. liicens. We regard it as most probable that the larva here described belongs to this 

 species. The same larva has been described by lUig from off the coast of Sierra Leone, 

 so that the range of S. prehensilis appears to extend up the west coast of Africa to north 



Q c 



Fig. 25. S. prehensilis. Acanthosoma 2. a, thorax; b, telson; c, eye. 



of the equator. Elaphocaris of the hispida type resembling those of S. lucens were taken 

 at Discovery Station 100 (Cape Town) and probably also belong to S. prehensilis. 



Nakazawa refers his species to S. prehensilis Bate (or S. phosphoreus Kishinouye), but 

 Hansen (1922, p. 35) has renamed the Japanese species S. lucens Hansen. 



UNIDENTIFIED LARVAE OF THE S. ROBUSTUS GROUP 



The Acanthosoma described above as that of S. robustus agrees with Hansen's 

 description, and nearly all specimens taken at Bermuda belong to the same species. 

 On the other hand, we have a number of specimens from the Discovery plankton, and 

 one from Bermuda, which differ more or less from this type and may be the larvae of 

 species hitherto not known as adults, or not recorded from the Atlantic. These may be 

 described as forms A, B, C. 



One of these may well be the larva of S. regalis, a species allied to S. robustus, which 

 has recently been described by Dr I. Gordon (Ann. Mag. Nat. Hist. (11), iv, p. 498, 1939). 



