HAYNES DESCRIPTION OF PA.WDALUS BOREALIS LARVAE 



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. 5 mm 



Figure 6. — Stage VI imegalopal of Pandalus bnrealis: A. ros- 

 trum, right side; B. t«lson. dorsal. 



remnants of a spine or two from Stage V. Trans- 

 verse hinge of exopodite of uropod complete. 



STAGES VII AND VIII (JUVENILES) 



Mean total length of Stage VII (first juvenile) 

 18.4 mm (range 15.1-21.0 mm; 5 specimens). Usu- 

 ally two setae between most rostral teeth. 

 Carapace without supraorbital spine. Arthro- 

 branchiae on third maxilliped and pereopods 1-4 

 present as minute buds. Mandibular palp present 

 for first time; three-segmented. Inner and outer 

 flagella of antennule each 11- to 13-segmented. 

 Exopodites on maxillipeds and pereopods 1-3 rem- 

 nant. Third abdominal somite sometimes bears 

 minute spine on middorsal posterior margin. Car- 

 pal joints of left and right second pereopods 28-30 

 and 14-17, respectively. Lateral margins of telson 



(Figure 7) typically bear 5 + 5 spines; posterior 

 margin rounded as in adult. 



Mean total length of Stage VIII (second 

 juvenile) 21.6 mm (range 19.0-23.6 mm; 8 speci- 

 mens). Morphological differences between Stages 

 VII and VIII slight. Most notable features of Stage 

 VIII: at least three or four setae between most 

 rostral spines; complete lack of exopodites on third 

 maxilliped and pereopods 1-3; inner and outer 

 flagella of antennule each 15- to 16-segmented; 

 lateral margins of telson typically bear 6 + 6 

 spines. 



COMPARISON OF LARVAL STAGES 



WITH DESCRIPTIONS BY 



OTHER AUTHORS 



The first description of larvae ascribed to Pan- 

 daliis horealiti was given by Sars ( 1900), based on 

 specimens collected from plankton. Berkeley 

 (1931) showed that Sars' larvae could not be P. 

 borealis; almost simultaneously Lebour (1930) 

 showed that they were Caridion gordoni (Bate). 

 Sars' "post-larval" specimen, however, is consid- 

 ered by both Lebour and Berkeley to be correctly 

 identified as P. borealis . As far as can be compared, 

 my Stage VI (megalopa) and Sars' "post-larval" 

 specimen are essentially identical except for the 



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0. 5 mm 



Figure 7.— Stage VII (first juvenilel of Pandalus borealis: tel- 

 son, dorsal. 



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