GORE: LARVAL DEVELOPMENT OF GALATHEA ROSTHATA 



FlClRE 7. — Galathea rostrata. fifth zoeal appendages: (A) An- 

 tennule; (B) antenna; iCi mandibles, lower view rotated ex- 

 teriorad ofzoea to show dentition; (Dl maxillule; (E) maxilla; (F) 

 maxilliped 1; iGi maxilliped 2; (H) maxilliped 3; (Ii telson; (ii 

 detail i,40 x objective), fifth telsonal process. Scale lines total 0.3 

 mm. 



plumose process appears making telson marginal 

 setal formula 8 + 9 as shown. 



Color: Chromatophores as follows: Red, on an- 

 terior margin of eyestalks, paired on carapace dor- 

 sally just behind eyes on frontal region, single 

 ventrolaterally beneath each eyestalk just above 

 mandibular region, ventrally on both antennular 

 and antennal peduncles at junction with carapace, 

 laterally on carapace above insertion of maxil- 

 liped 2; interiorly on mouth region on outer mar- 

 gin of mandible, posterior to mandible on maxil- 

 lule, and on midgut; abdominal somites 3-5 with 

 several groups laterally, plus a reddish-orange 

 line above hindgut of same. Orange 

 chromatophores in elongate streaks longitudi- 

 nally on basipodite of maxillipeds 1-3, more dif- 

 fused on maxillipedal endopodites, and in lateral 

 groupings on abdominal somites 3-5. Eyes blue- 

 green in reflected light, corneas dark, probably 

 black. 



Remarks: This stage followed the regular stage 

 IV and invariably molted to megalopal stage. 



Megalopa 



Carapace length x width: 1.7 x 1.2 mm. 

 Number of specimens examined: 4. 



Carapace: (Figure 8A, B). Resembling minia- 

 ture adult; rostrum triangular proximally, drawn 

 into sharp point distally, armed along lateral 

 margins with 4 distinct spines, some smaller 

 spinules occasionally interspersed; frontal region 

 with additional spinules as illustrated; 2 elongate 

 thickened setae on gastric region, plus other setae 

 and spinules as shown; lateral margins with 4 

 large spines, including 1 at epibranchial angle, 2 

 placed about equidistant behind, and the fourth at 

 junction with cervical groove; a variable number, 

 usually 3, smaller spines laterally between larger 

 spines; a fifth large spine on posterolateral mar- 

 gin, followed by another, smaller, dorsally and 

 posteriorly. Numerous small setae scattered over 

 entire carapace; eyes each with 2 large, feathery 

 setae on anterodorsal margin. 



AnU'iuutle: ( Figure 9A, a). Biramous; peduncle 

 large, three-segmented; basal segment inflated, 

 with 2 large forward-directed spines dorsally, 

 another, smaller, distoventrally; other setae as 

 shown; remaining two segments nearly smooth, 

 sparsely setose. Lower ramus three-segmented, 

 tip with 2 spinules (see detail. Figure 9a), other 

 setae as shown. Upper ramus six- or occasionally 

 indistinctly seven-segmented; aesthetascs on 

 segments two through five in the following se- 

 quence of rows and numbers: one row (2), two rows 

 (3, 3, + 2 setae), two rows (3, 2,-1-1 seta), one row 

 < 2 ); sixth segment with a single elongate terminal 

 seta plus other smaller setae. 



Antenna: (Figure 9B). Peduncle three- 

 segmented, heavily spined; flagellum with 2 or 3 

 fused segments plus a variable number ( about 24) 

 shorter segments each bearing 5 or 6 setae dis- 

 tally; terminal segment with 7 longer setae, as 

 illustrated. 



Mandible: (Figure 9C). Symmetrical, scoop- 

 shaped process, chitinized along leading margin; a 

 three-segmented palp, basal segment of which 

 bearing 2 short, spinelike setae, third segment 

 with about 13 or 14 stout, toothed spines. 



Maxillule: (Figure 9D). Endopodite now pos- 

 sessing but a single short, terminal seta. Basal 

 endite with 4 strong terminal setae, followed by 16 

 short, stout spines, 4 subterminal and 3 lateral 

 setae; a single seta basally as shown; coxal endite 

 lower portion extended into elongate, weakly 

 chitinized, lobe fringed with fine hairs; 3 basal 

 setae, 3 lateral setae, followed by 11 stout spines 

 and 8 strong setae terminally. 



Maxilla: (Figure 9E, e). Endopodite with a 

 single, long subterminal seta. Coxal and basal en- 

 dites heavily spinose and setose, numbers and po- 

 sition difficult to discern, but approximately as 

 follows: basal distal lobe, about 14 terminally, 4 + 

 2 subterminally, 2 laterally; proximal lobe, about 

 6 terminally, 3 + 1 subterminally, 1+2 laterally; 

 coxal distal lobe, about 3 each, terminally and 

 subterminally, 2 + 8 in irregular row laterally; 

 proximal lobe, about 11 placed more or less termi- 

 nally, 8 subterminally, 22 in a row encircling lobe 

 laterally, 1+2 beneath these; for exact position- 

 ing refer to outer (Figure 9E) or inner (Figure 9e) 

 views of lobes. Scaphognathite with about 40 



799 



