jointed with abdominal somite 6, has 8 + 8 

 densely plumose setae. Most of spinules at setal 

 bases and along terminal margin absent. Uro- 

 pods free. Endopodite of uropod about one-half 

 length of exopodite, has four setae along terminal 

 margin. Exopodite usually with 13 distal mar- 

 ginal setae and an outer subterminal spine. 



Comparison of Zoeal Stages with 

 Descriptions by Other Authors 



Of the described Spirontocaris zoeae, those of 

 S. murdochi are most similar to zoeae of S. 

 spinus (Sowerby), S. spinus intermedia Makarov, 

 and S. phippsii (Kr0yer): all have relatively long, 

 spiniform rostrums; exopodites on pereopods 1 

 and 2; and posterolateral spines on abdominal 

 somites 4 and 5. However, larvae of S. spinus 

 (described by Pike and Williamson 1961) and S. 

 spinus intermedia (described by Ivanov 1971) are 

 distinguishable from larvae of <S. murdochi: S. 

 spinus and S. spinus intermedia have a tuft of 

 setae on the dorsal surface of abdominal somite 4; 

 S. murdochi does not. Furthermore, in Stage I 

 zoeae of S. spinus and S. spinus intermedia , the 

 posterolateral spine on abdominal somite 5 is as 

 short as, or shorter than, the spine on abdominal 

 somite 4; whereas, in Stage I zoeae of S. mur- 

 dochi, the posterolateral spine on abdominal 

 somite 5 is noticeably longer than the posterolat- 

 eral spine on abdominal somite 4. 



Pike and Williamson (1961) described a Stage II 

 specimen of S. phippsii whose identity is assumed 

 from the distribution of adults in the northwest- 

 ern Atlantic Ocean. The specimen is described as 

 being nearly the same as Stage II S. spinus 

 except somewhat larger (6.0 mm). Also, the pos- 

 terolateral spines on abdominal somites 4 and 5 of 

 S. phippsii are "more prominent", the dorsal tuft 

 of setae on abdominal somite 4 is absent, the 

 telson is "broader", and the second pair of telsonic 

 spines are about three-fourths the length of the 

 third pair. This description is inadequate to dis- 

 tinguish between Stage II S. phippsii and Stage 

 II S. murdochi, except for total length: Stage II S. 

 murdochi average 3.7 mm total length compared 

 with 6.0 mm for S. phippsii. 



The Stage III zoeae described as "Spirontocaris 

 larva Nr. 2" by Stephensen (1916) from Greenland 

 waters are assumed to be S. phippsii (Pike and 

 Williamson 1961). When the figures and descrip- 

 tion of Stephensen's Stage III zoeae are compared 

 with my description of Stage III S. murdochi, S. 

 murdochi are smaller and noticeably less devel- 



oped. Stephensen's zoeae are 6.5 mm long, the 

 carapace has an antennal spine, the pleopods and 

 the chelae of pereopods 1 and 2 are clefted, and 

 telsonic setal pairs 3 and 4 are the same length. 

 My Stage III zoeae average 4.1 mm long, the 

 carapace does not have antennal spines, the pleo- 

 pods and chelae of pereopods 1 and 2 are not 

 clefted, and the third pair of telsonic setae are 

 noticeably shorter than the fourth pair of telsonic 

 setae. 



It should be noted, however, that this compar- 

 ison of zoeae of S. murdochi and S. phippsii is 

 based on specimens from different geographical 

 areas as well as specimens of S. phippsii that are 

 of unproven identity. Confirmation of morpholog- 

 ical development of S. phippsii larvae from the 

 North Pacific Ocean is desirable. 



Acknowledgment 



I thank Terry Butler, Pacific Biological Sta- 

 tion, Nanaimo, British Columbia, Canada, for 

 identifying the ovigerous female used in this 

 study. 



Literature Cited 



Haynes, E. 



1976. Description of zoeae of coonstripe shrimp, Pandalus 

 hypsinotus, reared in the laboratory. Fish. Bull., U.S. 

 74:323-342. 



1979. Description of larvae of the northern shrimp, 

 Pandalus borealis, reared in situ in Kachemak Bay, 

 Alaska. Fish. Bull., U.S. 77:157-173. 



1982. Description of larvae of the golden king crab, Lith- 

 odes aequispina, reared in the laboratory. Fish. Bull., 

 U.S. 80:305-313. 

 IVANOV, B. G. 



1971. Larvae of some far east shrimps in relation to their 

 taxonomic status (Linchinki nekotorykh dal'nevostoch- 

 nykh krevetok v svyazi s ikh sistematicheskim poloz- 

 heniem). Zool. Zh. 50:657-665. (Translated from Russ., 

 U.S. Dep. Commer, NOAA, Natl. Mar. Fish. Serv., Div. 

 Foreign Fish., Transl. IPST 651162, TT 72-50044.) 

 PIKE, R. B., AND D. I. WILLIAMSON. 



1961. The larvae of Spirontocaris and related genera 

 (Decapoda, Hippolytidae). Crustaceana 2:187-208. 

 STEPHENSEN, K. 



1916. Zoogeographical investigation of certain fjords in 

 southern Greenland, with special reference to Crustacea, 

 Pycnogonida and Echinodermata including a list of Al- 

 cyonaria and Pisces. Medd. Gronl. 53:230-378. 



EVAN B. HAYNES 



Northwest and Alaska Fisheries Center 



A uke Bay Laboratory 

 National Marine Fisheries Service, NOAA 

 P.O. Box 210155 

 Auke Bay, AK 99821 



528 



