species in morphology of this feature. The cor- 

 respondence between variation in morphology of 

 protozoeal stages and organs of Pesta within the 

 two species groups indicates that, with identifi- 

 cation of additional species, larval morphology 

 may prove useful in the study of interspecific re- 

 lationships within Sergestes, as predicted by 

 Gurney and Lebour (1940). 



The larvae of S. similis were also compared 

 with those of hispida type Sergia lucens (Omori 

 1969), one of the seven species comprising the 

 challengeri group. They were found to differ in 

 body armature, as expected from difference in 

 protozeal type, in form of telson, and in develop- 

 ment of some appendages, as shown in Table 2. 

 They also differ in number of naupliar stages. 

 Four distinct stages were observed in the 

 naupliar phase of Sergestes similis, while in 

 Sergia lucens nauplius I and II were found and 

 the latter developed gradually to molt into 

 protozoea I. When this finding is coupled with 

 the observations by Nakazawa (1916, 1932), they 

 suggest that there are zero to two molts during 

 the naupliar phase of S. lucens. An assessment of 

 the significance of these observations requires 

 additional knowledge of larval development 

 within the two closely related genera and their 

 species groups. 



FISHERY BULLETIN: VOL. 80, NO. 2 



ACKNOWLEDGMENTS 



This work was supported by the Marine Life 

 Research Program, the Scripps Institution of 

 Oceanography's component of the California 

 Cooperative Oceanic Fisheries Investigations. 



We are very grateful to Kuni Hulsemann and 

 her colleagues for a translation of Wasserloos 

 (1908), to A. Fleminger for the method and 

 materials to treat larvae with KOH and 

 Chlorazol Black E, and to E. Brinton for 

 criticism of the manuscript. 



LITERATURE CITED 



FOXTON. P. 



1972. Further evidence of the taxonomic importance of 

 the organs of Pesta in the genus Sergestes (Natantia, 

 Penaeidea). Crustaceana 22:181-189. 

 Gurney, R. 



1942. Larvae of decapod Crustacea. RaySoc. Publ. 129, 

 306 p. Ray Soc, Lond. 

 Gurney, R., and M. V. Lebour. 



1940. Larvae of decapod Crustacea. Part VI; The genus 

 Sergestes. Discovery Rep. 20:1-68. 

 Hansen, H. J. 



1922. Crustaces decapodes (Sergestides) provenant 

 des campagnes des yachts "Hirondelle" et "Princess 

 Alice" (1885-1915). Resultats des Campagnes Scien- 

 tifiques Accomplis sur son Yacht, par Albert I" 64:1- 

 232. 



Table 2.— Some differences between larvae of Sergestes similis and Sergia lucens. 



Feature 



Sergestes similis 



Sergia lucens 



Carapace armature: 

 Protozoea I 



Protozoea II 



Protozoea III 



Zoea l-ll 

 Postlarva I 



Abdomen armature; 

 Zoea l-ll 



Telson: 

 Zoea l-ll 



Postlarva I 



Antennule: 

 Zoea l-ll 



Antenna: 

 Zoea I 



Mandible: 



First maxilliped: 

 Zoea l-ll 



anterolateral process branches to 3 spines 



posterodorsal process a single spine with basal 

 spinules 



all processes with long spines which branch to spin- 

 ules distally 



rostrum with small spinules, armature ot other pro- 

 cesses as in II 



with 2 pairs lateral spines 



lateral spines remnants only, other spines present 



lateral spines decrease in length posteriorly, spines 1 

 and 2 with relatively long spinules in I 



fork with 2 outer and 2 inner spinules, invagination 

 does not reach lateral spines 



fork relatively wide with tiny spinules 



outer flagellum unsegmented in rarely 2- or 3-seg- 

 mented in II and shorter than peduncle 



endopod 8-segmented and longer than rostrum 

 palp appears in zoea I 



exopod with 13 or 14 setae 



anterolateral process branches to 4 spines 

 posterodorsal process branches to 3 spines 



all processes with small spinules only 



as in II 



with 3 pairs lateral spines 



rostrum and small posterodorsal spine present; supra- 

 orbital spine and basal spine of rostrum sometimes 

 present, lateral and hepatic spines missing 



lateral spines increase in length posteriorly, without long 

 spinules in I 



fork with 1 outer and 5/6 inner spinules in I, with 2 outer 

 spinules in II, invagination about as deep as lateral 

 spines 



fork narrow, with 2 large inner setae 



outer flagellum 2-segmented in I, ca. 8-segmented in II, 

 and longer than peduncle 



endopod 2-segmented and shorter than rostrum 

 palp appears in zoea II, rarely in zoea I 



exopod with 12 setae 



242 



