CONOR and CONOR: LARVAE OF FOUR PORCELLANIDAE 



endite; a small fanlike exite also present, 

 rimmed with very fine hairs. 



Maxilla II with unsegmented endopodite bear- 

 ing five setae. Basal endite bilobed: distal lobe 

 with approximately 26 setae; proximal lobe with 

 13 to 15 setae. Coxal endite bilobed: distal lobe 

 with nine marginal setae and six submarginal 

 setae, dorsal surface ; proximal lobe with about 

 20 marginal setae, 13 submarginals, dorsal 

 surface, and 8 submarginal setae, ventral sur- 

 face. Scaphognathite with approximately 50 

 marginal setae. 



Maxilliped I biramous. Exopodite devoid of 

 setae or hairs in specimens examined (two) . 

 Endopodite two-segmented in appearance, but 

 indistinctly so; distal segment bears two short 

 setae. Basal endite with 19 or 20 major mar- 

 ginal setae, 5 to 8 submarginal setae, dorsal 

 surface. Coxal endite with about seven major 

 marginal setae and six submarginal setae, three 

 on dorsal surface and three on ventral surface. 



Maxilliped II biramous. Exopodite consists 

 of two distinct segments, the distal segment it- 

 self appearing indistinctly segmented; there are 

 five to seven plumose setae on the distal segment 

 and five setae on the internal margin of the first 

 segment. Endopodite four-segmented, the distal 

 two segments each bearing dense brushes of ap- 

 proximately 20 to 30 setae; segment 2 with four 

 or five setae along distal margin; segment 1 with 

 approximately 11 setae along the internal 

 margin. 



Maxilliped III biramous. Exopodite incom- 

 pletely formed with two segments only; segment 

 2 with one small proximal seta. Endopodite 

 specialized for filter feeding and consists of five 

 segments; segment 2 with 10 to 12 major setae, 

 dorsal internal margin; segment 3 with 9 or 10 

 major feeding setae, 3 or 4 short, stout brushlike 

 setae, and 2 or 3 very short, spikelike setae all 

 on the dorsal internal margin; segment 4 with 

 nine major feeding setae along the internal 

 ventral margin, six or seven minor feeding setae 

 along dorsal internal margin; four or five major 

 brush setae and two spikes, all along internal 

 dorsal margin ; segment 5 with six pairs of feed- 



ing setae and two minor brush setae terminally; 

 other setation as pictured. 



Pereiopods well developed and functional. 

 Chelipeds slender and streamlined, generally 

 dorsoventrally flattened with fine bristles over 

 entire surface; outer margin of chelae produced 

 in a series of spines; anterior margin of carpus 

 with one major spine and a fine bristle associated 

 with it. Pereiopods 2, 3, and 4 similar to each 

 other in shape and setation as figured (Figure 

 51). Pereiopod 5 chelate and armed with setae 

 and bristles as shown; four to eight scythelike 

 cleaning setae (Figure IL, N) are also present. 



Abdomen six-segmented; segments 2 through 

 5 each bearing one pair of pleopods. Pleopods 

 biramous; exopodite with 16 plumose marginal 

 setae; endopodite with two short setae and four 

 hooks on margin. A single primary red chro- 

 matophore located on segment 2 or betw^een 2 

 and 3. Segment 6 of the abdomen bears a pair of 

 biramous uropods, the outer ramus usually hav- 

 ing 14 and inner ramus with 15 marginal setae. 

 Telson with 14 to 16 major plumose setae and 

 14 to 16 minor setae located between the major 

 marginal setae. The dorsal surface of the telson 

 bears a number of symmetrically placed pairs 

 of fine hairs. In megalopae of advanced age, 

 the beginning of the division of the telson into 

 five plates can be seen beneath the cuticle. Up- 

 on molting to the first crab stage, the division 

 of the telson is complete and distinct. 



LARVAL DEVELOPMENT OF 

 PETROLISTHES ERIOMERUS STIMPSON 



Larvae of P. eriomerus were reared in un- 

 aerated Erlenmeyer flask cultures. 



PREZOEA 



The prezoea has essentially the same form as 

 that described for P. cinctipes and diflfers only 

 in one pair of primary chromatophores. P. 

 eriomenis prezoeae lack the chromatophore on 

 either side of the body between the bases of 

 maxillipeds I and II which occurs in P. cinctipes 

 larvae. 



201 



