KNIGHT: LARVAL DEVELOPMENT OF EUPHAUSIA EXIMIA 



Leg 5 endopod with 4 or 5 (5) segments and 1-5 

 (2) terminal setae; exopod with 0-5 (0-2) setae; gill 

 with bud of third lobe. 



Leg 6 endopod unsegmented with or 1 (0) ter- 

 minal seta; exopod nonsetose and gill with two or 

 three lobes. 



Legs 7 and 8 with more than three gill lobes. 



Abdomen with pigmented photophores on seg- 

 ments 1,2, and 4, photophore on segment 3 some- 

 times with visible structure and some pigment. 



Telson (Figure 6h) with 1 terminal and 3 pairs of 

 posterolateral spines; telson of next instar when 

 visible beneath cuticle with only 2 pairs postero- 

 lateral spines in 38% of 77 larvae; 9T7c of 71 fur- 

 cilia V with 2 pairs lateral spines. 



FURCILIA VI (FIGURE 7F). — Carapace with 

 smooth lateral margins on well-developed ros- 

 trum. 



Antennule with lateral spine about equal or less 

 than length of peduncle segment 2, dorsal lappet of 

 segment 1 with small knob or few spines (Figure 

 7h-2). 



Antennal scale with 15-18 ( 16) setae; flagella no 

 longer intact in preserved specimens. 



Mandibles (Figure 4e) with palp relatively long, 

 usually unsegmented, sometimes constricted into 

 2 or 3 weakly defined segments; 1 of 18 furcilia VI 

 with 1 terminal seta on 2-segmented palp; slender 

 terminally dentate plate near molar area of each 

 mandible reduced, sometimes missing on left 

 mandible. 



Maxilliped continues to lengthen to juvenile 

 form, endopod 5-segmented and setose, exopod 

 still with 1 proximal and 4 distal setae, coxa with- 

 out long seta on posterior face. 



Leg 2 exopod with 6-8 (6-7) setae, 14 of 17 ap- 

 pendages examined with additional proximal seta 

 on inner margin (Figure lOe); gill with four lobes. 



Leg 3 exopod with 6-8 (6) setae, 22 of 24 appen- 

 dages with proximal seta; gill with four lobes. 



Leg 4 exopod with 6 or 7 (6) setae, 4 of 21 appen- 

 dages with proximal seta; gill with four lobes. 



Leg 5 endopod 5-segmented and setose; exopod 

 with 4-6 (5) setae; gill with four lobes. 



Leg 6 endopod with 0-5 (0-3) segments and 0-2 

 (1) terminal setae; exopod with 0-3 (0) setae; gill 

 with four or more lobes. 



Legs 7 and 8 with branching gill lobes, rudiment 

 of leg 7 sometimes with terminal seta (Figure 

 lOf). 



Abdomen with photophores pigmented on seg- 

 ments 1-4. 



Telson (Figure 6i) with 3 or 2 (in 32% of 59 

 larvae) pairs of posterolateral spines, developing 

 telson of next instar when visible beneath cuticle 

 with 2 pairs posterolateral spines in 18 of 19 lar- 

 vae; 947c of 52 furcilia VI with 2 pairs of lateral 

 spines. 



JUVENILE I (FIGURES 7G, 90). — Carapace 

 with lengthening rostrum. 



Antennule with lateral spine from slightly less 

 than to about one-third the length of peduncle 

 segment 2, lappet with 3-6 spines (Figure 7h-3). 



Antennal scale with 16-19 (18) setae. 



Mandibles (Figure 4f) with palp usually three- 

 segmented, sometimes with 1 terminal seta and 

 0-3 lateral setae on segment 2, median armature 

 as in furcilia VI. 



Maxillule without or with seta on anterior mar- 

 gin of pseudexopod and maxilla with increasing 

 numbers of setae on endopod and exopod ( Tables 4, 

 5; Figure 10 c-d). 



Leg 1 (maxilliped) exopod with 4-7 (4) setae. 



Leg 2 exopod (Figure lOe) with 6-8 (8) setae, all 

 with additional proximal seta on inner margin; 

 gill with four lobes. 



Leg 3 exopod with 6-8 (8) setae plus proximal 

 seta on inner margin; gill with four lobes. 



Leg 4 exopod with 6-8 (6-7) setae, 12 of 20 ap- 

 pendages with proximal seta; gill with four lobes. 



Leg 5 exopod with 5-8 (6-7) setae, 3 of 17 appen- 

 dages with proximal seta; gill with four lobes. 



Leg 6 endopod with 4 or 5 (5) segments and 2-4 

 (2) terminal setae; exopod with 2-6 (2-3) setae; gill 

 many branched. 



Legs 7 and 8 (Figure lOf-g) rudiments each with 

 terminal seta and ramified gills. 



Telson (Figure 6j) usually with 2 pairs postero- 

 lateral and 2 pairs lateral spines (in 92% and 98% 

 of 53 larvae). 



In E.eximia, as in E . gibboides , the reduction in 

 number of terminal telson spines appears not to be 

 a reliable single guide to recognition of develop- 

 mental stages in furcilia IV-VI but rather only one 

 of a group of features that characterize these 

 stages. Furcilia IV of E. eximia, as delimited in 

 this study, had a variable number of terminal 

 spines which overlapped with the number of ter- 

 minal telson spines in furcilia III and V. Furcilia 

 IV differed from furcilia III, however, in the fol- 

 lowing features: modification of both antenna and 

 mandible; segmentation of antennular flagellum; 

 setation of exopods of legs 2 and 3; setation and 

 segmentation of leg 4 endopod; and setation of 



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