PEREZ FARFANTE: REVISION OF GENUS PSEUDARISTEUS 



lateral spines and 2 elongate cicatrices. Telson with 

 median sulcus well defined only on anterior 0.33 

 length of telson and flanked by paired longitudinal, 

 slender ridges reaching base of third of 4 pairs of 

 movable, marginal spines: 3 situated at about 0.65, 

 0.80, and 0.90 length from basal margin of telson, 

 fourth flanking short terminal part. Mesial ramus 

 of uropod surpassing apex of telson by about 0.40 

 its own length; lateral ramus overreaching mesial 

 ramus by about 0.33 its own length. 



Petasma in adults (Fig. 16/1, 5) vdth dorsomedian 

 lobule cincinnulate along entire mesial margin. Ven- 

 tromedian lobule, extending distally as far as dor- 

 solateral lobule, and bearing elongate, lapel-like flap 

 distoventrally along mesial margin. Dorsolateral 

 lobule sclerotized, broad proximally to about base 

 of distal 0.25, then tapering to subacute mesial apex, 

 ventrally bearing conspicuous longitudinal, arched 

 rib and studded with setae. Ventral costa broadly 

 curved along almost entire length, inclined disto- 



FlGURE l^.—Pseudaristeus gracilis, Petasmata: A, cr20 mm CL, eastern Mindanao Sea, Philippines, 

 dorsal view of left half. B, Ventral view. C, Syntype o" 13 mm CL, Tablas Island, Philippines, dorsal 

 view of left half. D, Ventral view. Scales: A, B = 1 mm; C, D, = 0.5 mm. 



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