FISHERY BULLETIN: VOL. 74, NO. 2 



faint or distinct near acute tip. No supraorbital 

 spine in this or remaining stages (Figure 4A). 

 Small setae and groups of minute hairs irregu- 

 larly located on carapace. 



ANTENNULE (FIGURE 4B).— Outer flagel- 

 lum four segmented and longer than in Stage III 

 beginning to acquire slender terminal portion as 

 in adult; five groups of aesthetascs, two groups on 

 first and second segments each and one group on 

 third; groups composed of 3, 3, 3, 4, and 5 aes- 

 thetascs. Inner flagellum four segmented, nearly 

 as long as outer flagellum. Rest of antennule 

 similar in shape to Stage III but larger; bears 

 additional spines and setae; lateral projection on 

 proximal segment more pronounced, and ventral 

 spine on proximal segment noticeably smaller 

 than in Stage III. 



ANTENNA (FIGURE 4C).— Antennal scale 

 with 32-39 lateral plumose setae and is assuming 

 narrow, slightly curved form of adult; scale bears a 

 few simple setae medially and usually a large seta 

 on inner margin near tip. Inner flagellum not 

 much longer than Stage III, about SVz times 

 length of scale. 



MANDIBLES (FIGURE 4D).— Incisor and mo- 

 lar processes of both mandibles separated by deep 

 cleft, and each mandible has unsegmented palp 

 bearing two setae terminally. Curved lip of right 

 mandible considerably larger than in Stage III. 



MAXILLULE.— Similar to Stage III except 

 number of setae somewhat variable. Endopodite 

 usually has one seta but may bear additional 

 small setae. Basipodite has 12 spines and 9-13 

 setae terminally, 2 or 3 setae subterminally. Cox- 

 opodite usually has 15 setae. 



MAXILLA (FIGURE 4E).— Exopodite fringed, 

 has 32 plumose setae in addition to plumose seta 

 at proximal end; separated from protopodite by 

 cleft and bears 3 setae along inner margin. Num- 

 ber of setae on endopodite reduced to four. Basi- 

 podite bears 12 setae on each lobe; proximal lobe 

 bears additional seta subterminally. Distal lobe of 

 coxopodite reduced in size and bears two setae 

 instead of four as in Stage HI; proximal lobe of 

 coxopodite bears eight long and five short setae. 



FIRST MAXILLIPED (FIGURE 4F).— Epipo- 

 dite distinctly bilobed. Protopodite clearly two 

 segmented and bears 6 setae on proximal seg- 

 ment, 26 smaller setae on distal segment. Endopo- 

 dite three segmented and bears one long seta on 

 first segment and one long and one short setae 

 terminally on third segment. Exopodite bears 6 

 long plumose setae along proximal outer margin 

 and 9 or 10 natatory setae. 



SECOND MAXILLIPED (FIGURE 4G).— Sec- 

 ond maxilliped has undergone considerable change 

 from Stage III and now is similar in shape to adult. 

 Endopodite five segmented; terminal segment 

 flattened with many short spinous setae on lateral 

 margins. Epipodite arises from coxopodite and is 

 single lobed. 



THIRD MAXILLIPED (FIGURE 4H).— Exopo- 

 dite considerably reduced. Endopodite heavily 

 setose and spinous. Meropodite slightly enlarged 

 medially; not distinctly segmented from ischiopo- 

 dite. Basipodite enlarged medially somewhat 

 more than meropodite. Bud of mastigobranchia 

 arises from coxopodite. 



FIRST PEREOPOD (FIGURE 41).— Exopodite 

 reduced as in preceding appendage. Endopodite 

 ends in simple, heavily setose conical dactyl, as in 

 the third maxilliped; ischiopodite articulates 

 somewhat laterally with meropodite. Pereopods of 

 this stage, except fifth pair, bear bud of masti- 

 gobranchia. Each pleurobranchia adult in shape 

 and clearly lobulated. 



SECOND PEREOPOD (FIGURE 4J).— Exopo- 

 dite reduced in size as in third maxilliped and first 

 pereopod. Joints appear on carpal segment for 

 first time, 10 or 11 on left and 5-7 on right. Left 

 pereopod slightly longer (about one-tenth) than 

 right pereopod. 



THIRD, FOURTH, AND FIFTH PEREOPODS. 

 — Essentially similar to pereopods of Stage III. 



PLEOPODS (FIGURE 4A).— Pleopods cleft 

 slightly and without joints or setae. 



TELSON (FIGURE 4K).— Lateral margins 

 nearly parallel but spaced slightly wider posteri- 

 orly and bear two spines on each margin. Termi- 

 nal margin straight and bears three pairs of 

 feathered spines, the second pair longest; two 



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