FISHERY BULLETIN: VOL. 71, NO. 1 



flagellum two-segmented with four setae ter- 

 minally and two subterminally; outer flagellum 

 with four segments; proximal segment naked, 

 the antepenultimate segments with six aesthetes, 

 penultimate with five aesthetes and one seta, dis- 

 tal segment with five aesthetes near its base and 

 one seta subterminally, terminating in a long, 

 plumose seta. The basal portion of the antenna 

 (Figure 6C) is two-segmented with small setae 

 scattered on the distal segment; peduncle two- 

 segmented with three setae on each segment; 

 the flagellum is eight-segmented, the setation 

 as figured. Mandibular palp two-segmented with 

 16 setae on the distal segment (Figure 6D) . The 

 endopodite of the maxillule (Figure 6E) is un- 

 segmented, has one lateral and two subterminal 

 setae, and terminates in a spine; the basal en- 

 dite bears about 35 spinous setae; the coxal en- 

 dite with about 25. The scaphognathite of the 

 maxilla (Figure 6F) with about 100 marginal 

 plumose setae, with a few setae scattered on the 

 dorsal and ventral surfaces; endopodite pro- 

 duced into a narrow lobe, with three setae on 

 the distal margin of the base, eight setae lat- 

 erally on the same margin, and one long setae 

 on the proximate lateral edge; basal endite with 

 about 14 spinous setae on the distal lobe, 11 on 

 the proximal; coxal endite with eight spinous 

 setae on the distal lobe and 16 on the proximal. 

 The exopodite of the first maxilliped (Figure 

 6G) now terminates in but five plumose setae 

 and one naked seta; the endopodite is unsegment- 

 ed and bladelike; basal endite with about 37 spi- 

 nous setae along the margin; coxal endite with 

 12; epipodite with about 16 nonplumose hairs 

 and 1 seta; setation of other portions as figured. 

 A well-developed epipodite is present on the 

 second maxilliped (Figure 7B) and bears 

 about 14 nonplumose hairs and 2 setae; the 

 exopodite terminates in four plumose and one 

 nonplumose setae, and there are four short setae 

 on the outer lateral margin; the endopodite with 

 four segments, the distal segment with about 

 13 spinous setae terminally; other setation as 

 figured. The exopodite of the third maxilliped 

 (Figure 7C) terminates in six plumose setae; 

 the endopodite is five-segmented, its spination 

 and setation variable as is that of the epipodite 

 and is approximately as figured. Chelipeds (Fig- 



ure 7E) with a strong hooked spine on ventral 

 portion of ischum. Spines on coxa of pereiopods 

 one through three and another blunt spine sub- 

 terminally on the posterior margin of the same 

 articulation, decreasing in size posteriorly. 

 Dactyl of last pereiopod with two curved, toothed 

 setae (Figure 7F and G), 



DISCUSSION 



The prezoea and first zoea stages of Geryon 

 qiiinquedens appear to be quite similar in struc- 

 ture to the corresponding stages of G. tridens 

 described by Brattegard and Sankarankutty 

 (1967) . The most trenchant diff"erences are the 

 larger size of the zoea of G. quinqiiedens and the 

 lack of posterolateral spines on the fifth abdom- 

 inal somite in G. tridens. Brattegard and Sank- 

 arankutty give the length of the first zoea as 

 2.0 mm but no mention is made as to how they 

 arrived at this measurement. The large size 

 of the larvae of G. quinqiiedens should help to 

 distinguish them from other sympatric Brachy- 

 rhyncha, with the possible exception of its 

 congener, G. affinis. 



The family Geryonidae was erected in 1930 

 by Beurlen (original reference not obtained, in- 

 formation from Christiansen, 1969), but since 

 then Geryon has been placed in various families: 

 Rathbun (1937) places Geryon quinqiiedens in 

 the subfamily Carcinoplacinae of the family 

 Goneplacidae; Bouvier (1940) placed Ger?/on in 

 the family Xanthidae; Gurney (1939) lists the 

 genus under the subfamily Menippinae of the 

 family Xanthidae; and more recently Christian- 

 sen (1969) reassigned the genus to the family 

 Geryonidae, 



I have found few references dealing with the 

 larvae of goneplacid genera. Lebour (1928) dis- 

 cussed the larval stages of Gonoplax rhomboides; 

 Kurata (1968) described the larvae of Carcino- 

 plax longimanus. Both of these species agree 

 generally with Geryon in the number of larval 

 stages, the spination of the carapace and abdo- 

 men, and the spination and setation of the telson. 

 The relative length of the exopodite to the pro- 

 topodite of the antenna in Geryon is apparently 

 similar to that in Carcinoplax but diff'erent from 

 that in Gonoplax. Megalopa of both Gonoplax 



80 



