FISHERY BULLETIN: VOL. 74, NO. 2 



The density of nauplii was controlled only to the 

 extent that a few nauplii remained in the con- 

 tainer at the end of each feeding period. The origi- 

 nal beakers and vials were used throughout the 

 study because the zoeae also fed on the algae that 

 grew on the sides and bottoms. 



All zoeae molted at night. Of the deaths noted, 

 most were caused by failure to complete the molt- 

 ing process; the posterior half was shed success- 

 fully, but the anterior half remained attached to 

 the mouth parts and pereopods. Survival was 

 about 90%. 



Illustrations were drawn from unstained zoeae 

 and from exuviae stained red with Turtox CMC-S^ 

 (acid fuchsin stain mountant). Stained exuviae 

 show segmentation and setation more clearly 

 than unstained. Zoeae and exuviae were dissected 

 with the aid of a binocular dissecting microscope. 

 The dissected material was mounted on a slide 

 and drawn to scale with the aid of a camera 

 lucida. Detail was checked with a compound mi- 

 croscope up to 430 X. 



In the final illustrations (Figures 1-6), for clar- 

 ity, setules on the setae are usually omitted but 

 spinulose setae are shown. Because the numbers 

 of setae on the surface of the carapace and abdo- 

 men are highly variable, especially from Stage IV 

 onward, they are figured only when useful in iden- 

 tification of a stage. For each pair of appendages 

 the left member is figured except for the mandi- 

 bles, which are drawn in pairs and figured from 

 the right side. Whole zoeae are also figured from 

 the right side. The figures are in part schematic 

 and represent typical setal counts. The setation 

 formulas proceed from the distal to the proximal 

 ends of appendages. Gill development is men- 

 tioned in the text but usually not shown in the 

 figures. The terms are defined as follows: 



spinose — bearing many spines 

 spinous — spinelike 

 setose — set with bristles (setae) 

 spinulose — set with little spines. 



Total length was measured from the anterior tip of 

 the rostrum to the posterior tip of the telson with 

 the aid of a dissecting microscope; the number of 

 specimens used to determine total lengths is given 

 for each stage. A minimum of 10 exuviae of each 

 stage was used to verify segmentation and seta- 

 tion unless noted otherwise. The term "stage" 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



denotes the intermolt period. Nomenclature of 

 larval appendages and gills follows Pike and 

 Williamson (1964) and Berkeley (1930) respec- 

 tively. 



STAGE I ZOEA 



Total length of Stage I zoea (Figure lA) 5.8 mm 

 (range 5.5-6.2 mm; 50 specimens). Live specimens 

 brightly colored by numerous yellow chromato- 

 phores edged reddish browm. A conspicuous yel- 

 low chromatophore occurs dorsally on each eye- 

 stalk and at base of telson. Smaller but distinct 

 chromatophores occur on nearly all appendages, 

 especially maxillipeds and pereopods. Tips of an- 

 tennule and antennal scale are tinged reddish 

 brown. Chromatophore pattern of specimens 

 preserved in 5% solution of Formalin and sea- 

 water for several days identical to the pattern on 

 live specimens except that yellow color changes to 

 reddish brown after preservation. Rostrum slen- 

 der, spiniform, without teeth, about one-third 

 length of carapace, and projects horizontally or 

 slightly downward. Carapace with small, some- 

 what angular dorsal prominence at base of ros- 

 trum and a smaller rounded prominence near 

 posterior edge; prominences occur in all zoeal 

 stages. Antennal and pterygostomian spines 

 present, but both usually hidden by sessile eyes; 

 no supraorbital spine. 



ANTENNULE (FIGURE IB).— Antennule (first 

 antenna) consists of a simple unsegmented tubu- 

 lar basal portion, distal conical base, distal conical 

 projection, and a heavily plumose seta on a small 

 conical base; distal conical projection bears four 

 aesthetascs — one long, one short, and two of inter- 

 mediate length. 



ANTENNA (FIGURE IC).— Antenna consists 

 of inner flagellum (endopodite) and outer antennal 

 scale (exopodite). Flagellum two segmented and 

 about one-fourth longer than scale; distal segment 

 is styliform, tipped by a plumose seta and a spine. 

 Distal segment may be partially segmented proxi- 

 mally. Protopodite bears spinous seta at base of 

 flagellum and a spine at base of scale, both of 

 which persist throughout zoeal development. An- 

 tennal scale distally divided into six segments 

 (two proximal joints incomplete) and fringed with 

 10 heavily plumose setae along terminal and in- 

 ner margins. A small seta occurs on outer margin 

 near base of terminal segments. 



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