FISHERY BULLETIN: VOL 76, NO. 1 



Stages I and II are described in greatest detail 

 because these stages are the most difficult to iden- 

 tify. Terminology, methods of measuring, 

 techniques of illustration, and nomenclature of 

 gills and appendages follow Haynes ( 1976). Com- 

 parison of larvae from plankton with cast skins 

 from flasks was facilitated by first clearing the 

 larvae in 10*?^ KOH. 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. For clarity, setules on setae are 

 usually omitted but spinulose setae are shown. 



STAGE I ZOEA 



Total length of Stage I (Figure lA) 4.0 mm 

 (range 3.7-4.2 mm; 10 specimens). Live specimens 

 translucent with isolated areas of color: mouth- 

 parts orange with a bright yellow chromatophore 

 at base; internal thoracic organs greenish, espe- 

 cially heart area; base of maxillipeds greenish 

 orange; distinct yellow chromatophore at anus. 

 Rostrum slender, spiniform, without teeth, about 

 one-third length of carapace, and projects horizon- 

 tally or slightly downward. Carapace with small, 

 somewhat angular dorsal prominence at base of 

 rostrum and a smaller rounded prominence near 

 posterior edge. These two prominences occur in all 

 zoeal stages. Pterygostomian spines present but 

 usually hidden by sessile eyes. Three to four mi- 

 nute spinules along ventral margin of carapace 

 immediately posterior to pterygostomian spine 

 (spinules not shown in Figure lA). These spinules 

 usually occur in all zoeal stages but may vary in 

 number from two to five not only between stages 

 but among individuals within a given stage. 



ANTENNULE (Figure IB).— First antenna, or 

 antennule, consists of a simple unsegmented tubu- 

 lar basal portion with a heavily plumose seta ter- 

 minally and a distal conical projection bearing 

 four aesthetascs: one long, one short, and two of 

 intermediate length. 



ANTENNA (Figure IC).— Consists of inner 

 flagellum (endopodite) and outer antennal scale 

 (exopodite). Flagellum unsegmented, slightly 

 shorter than scale, styliform, and tipped by a 

 spinulose spine. Antennal scale distally divided 

 into five joints (the proximal joint incomplete) and 

 fringed with nine heavily plumose setae. Two 

 simple setae occur on outer margin, one terminal 

 and adjacent to plumose setae and the other near 



238 



base of terminal segments. A small plumose seta 

 usually occurs proximally near lateral margin in 

 all zoeal stages. Protopodite bears spinous seta at 

 base of flagellum but no spine at base of scale. 



MANDIBLES (Figure ID).— Without palps in all 

 zoeal stages. Incisor process of left mandible bears 

 four teeth in contrast to triserrate incisor process 

 of right mandible. Left mandible bears a movable 

 premolar denticle (lacinia mobilis) whereas right 

 mandible bears two immobile premolar denticles. 

 Truncated molar process of left mandible bears a 

 subterminal tooth that occurs throughout all zoeal 

 stages. 



MAXILLULE (Figure IE).— First maxilla, or 

 maxillule, bears coxal and basial endites and an 

 endopodite. Proximal lobe (coxopodite) bears stout 

 seta near base, and seven spinulose spines termi- 

 nally. Median lobe (basipodite) bears five stout 

 spinulose spines on terminal margin, two of them 

 especially thick with projecting teeth, and a large 

 setose seta proximally. Endopodite originates 

 from lateral margin of basipodite and bears three 

 terminal and two subterminal setae; two of the 

 setae are especially spinulose. 



MAXILLA (Figure IF). — Bears platelike exopo- 

 dite ( scaphognathite) with four long plumose setae 

 along distal and outer margins, and one slightly 

 longer and thicker seta at proximal end. Endopo- 

 dite gives indication of four partly fused segments 

 and bears nine large plumose setae. Basipodite 

 bilobed; each lobe bears six setae. Bilobed coxopo- 

 dite bears 15 setae, 4 on distal lobe and 11 on 

 proximal lobe. Four setae, one on each lobe of 

 basipodite and coxopodite, bear a row of little 

 spines along entire length. 



FIRST MAXILLIPED (Figure IG).— Most heavily 

 setose of natatory appendages. Protopodite not 

 segmented; bears 17-20 setae, several of them 

 especially spinulose. Endopodite distinctly four- 

 segmented; setation formula 4, 2, 1, 3. Exopodite a 

 long slender ramus segmented at base; has two 

 terminal and two lateral natatory setae. Epipodite 

 a single lobe. 



SECOND MAXILLIPED (Figure IH).— Protopo- 

 dite not segmented; bears nine sparsely plumose 

 setae. Endopodite distinctly four-segmented; seta- 

 tion formula 6, 2, 1, 3. Exopodite with two termi- 

 nal, six lateral natatory setae. No epipodite. 



