FISHERY BULLETIN: VOL 79, NO. 3 



because S. spina intermedia has a tuft of setae on 

 the dorsal surface of the fourth abdominal somite. 



Spirontocaris ochotensis 



When descriptions of hippolytid zoeae by other 

 authors (Stephensen 1916, 1935; Webb 1921; 

 Lebour 1931, 1932; Needier 1934; Frost 1936; 

 Gurney 1942; Williamson 1957; Pike and William- 

 son 1961; Makarov 1967; Ivanov 1971; and Haynes 

 1978) are compared with my description of zoeae of 

 S. ochotensis , my Stage I zoeae of S. ochotensis are 

 the only described hippolytid zoeae of the northern 

 North Pacific Ocean that have posterolateral 

 spines on the fourth and fifth abdominal somites 

 and lack a rostrum. Stage I zoeae of S. arcuata 

 (described in this report) are similar to Stage I S. 

 ochotensis zoeae but have a rostrum. 



Heptacarpus camtschaticus 



The only larvae of Heptacarpus identified are 

 the first zoeal stages of three species that Needier 

 (1934) described: H. paludicola , H. tridens , and H. 

 breuirostris. These zoeae differ from H. camtschat- 

 icus: Needler's zoeae lack a rostrum, a spine 

 adjacent to the plumose seta of the antennule, and 

 a long proximal seta on the scaphognathite of the 

 maxilla. Also, Needler's zoeae have pterygosto- 

 mian spines, which are absent in Stage I zoeae of 

 H. camtschaticus. 



Stage I zoeae that resemble Stage I zoeae of H. 

 camtschaticus include E. pusiolus and E. occultus 

 found in European waters (Pike and Williamson 

 1961) and E. macilentus found in the Bering Sea 

 (Ivanov 1971). All these Stage I zoeae lack postero- 

 lateral spines on the fourth and fifth abdominal 

 somites and have a minute rostrum (although 

 Stage I zoeae of E. occultus from British waters 

 may lack a rostrum [Pike and Williamson 1961]). 

 Stage I zoeae of H. camtschaticus differ from the 

 other Stage I zoeae because H. camtschaticus 

 zoeae have all pairs of pereopods, and the antennal 

 flagellum projects only about three-fourths the 

 length of the antennal scale. In Stage I, the other 

 species lack pereopods, and the antennal flagel- 

 lum projects to the tip of the antennal scale or just 

 beyond. In addition. Stage I zoeae of E. occultus 

 have a small dorsal tuft of setae on the fourth 

 abdominal somite and a row of fine denticles 

 on the posterior margin of the fifth abdominal 

 somite; these structures are absent in Stage I 

 zoeae of H. camtschaticus. 



CHARACTERIZATION OF ZOEAE OF 



SPIROMTOCARIS S.S. AND 



RELATED GENERA 



Holthuis (1947) redefined the genus Spironto- 

 caris sensu lato (s.l.) and divided it into six genera: 

 Birulia, Eualus, Heptacarpus, Lebbe us, Spironto- 

 caris sensu stricto (s.s.), and Thoralus. Pike and 

 Williamson (1961) categorized the zoeae of Spiron- 

 tocaris s.l. by the number of zoeal stages, number 

 of pereopods, morphology of the rostrum in Stage 

 I, and number of pereopods with exopodites in the 

 last zoeal stage. Because of the wide range in 

 morphology of the zoeae. Pike and Williamson 

 (1961) suggested that Spirontocaris s.l. be given 

 suprageneric status. My descriptions of hippolytid 

 zoeae partially invalidate Pike and Williamson's 

 categorization, extend the range of larval char- 

 acters of the genus Spirontocaris s.l., and confirm 

 Pike and Williamson's suggestion that Spironto- 

 caris s.l. be given suprageneric status. 



In Pike and Williamson's (1961) categorization, 

 the known larvae of Lebbeus and Spirontocaris 

 s.s. form separate generic groups. They categorize 

 identified larvae of Eualus spp. into two distinct 

 groups. Group 1 includes E. gaimardii, which has 

 five zoeal stages. In Stage I zoeae of Group 1, the 

 rostrum is large, and four pairs of undeveloped 

 pereopods are present; in later zoeal stages, exopo- 

 dites are present on pereopods one through three. 

 Group 2 includes E. pusiolus, E. occultus, E. 

 fabricii, and E. herdmani, which probably have 

 six to nine zoeal stages. In Stage I zoeae of Group 2, 

 the rostrum is minute or absent, and there are no 

 pereopods. In later zoeae, exopodites are present 

 on pereopods one through four (evidence was 

 incomplete for E. fabricii and E. herdmani). The 

 lack of information on larvae of Heptacarpus spp. 

 prevents any comparison of Heptacarpus spp. 

 larvae to those of Group 2 Eualus. 



My descriptions of zoeae of L. polaris, E. suck- 

 leyi, E. fabricii, S. arcuata, S. ochotensis, and H. 

 camtschaticus increase the range of morphological 

 variations of zoeal "generic" characters used by 

 Pike and Williamson (1961) for these genera 

 (Table 3). Pike and Williamson list the rostrum of 

 Lebbeus spp. zoeae in Stage I as small, but the 

 rostrum may also be large (about one-half the 

 length of the carapace). They list the rostrum in 

 Stage I zoeae of Spirontocaris s.s. as large, but 

 the rostrum of Stage I zoeae of S. arcuata is 

 small (about one-seventh the length of the cara- 

 pace), and the rostrum of Stage I zoeae of S. 



438 



