16 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
Fifth leg: Merus, relatively stout (B/L ca. 1.5), posterodistal border 
coarsely serrated. 
Third maxilliped: Anteroexternal angle conspicuously expanded in 
lateral direction. 
Male abdomen: Elongate, ultimate segment lanceolate with rounded 
tip, twice as long as broad. Penultimate segment, distally parallel 
sided, then converging regularly, 1.4 times as long as broad. 
Male first pleopod: Short, stout, robust, smoothly but conspicuously 
curved. Subterminal armature on outer surface, of scattered spinules 
with portions of three or four (only) visible in profile view. Inner 
side without subterminal armature or with a single bristle in profile 
view. Under surface with scattered reasonably numerous spinules. 
Remarks.—This species differs considerably from P. hastatordes, 
although it keys out similarly in Stephenson and Campbell (1959). It 
differs obviously in the carapace ornamentation. 
The strongly embossed carapace is reminiscent of P. petreus, but the 
present species differs as follows: Spines on inner and outer sides of 
wrist are approximately equal size; last anterolateral tooth is dis- 
tinctly longer (see Crosnier, 1962, fig. 86, pl. 4, fig. 1); has angled 
posterior-posterolateral junctions of the carapace. 
It resembles P. rugosus in its embossed carapace but differs in the 
details of granulation and in having a 4-lobed front. 
It possibly resembles P. tuberculosus more closely than any other 
species but differs in having: A more conspicuously produced antero- 
external border of the merus of the third maxilliped; less protruding 
median frontal teeth; a much larger first anterolateral tooth; a longer 
ninth anterolateral tooth; a differently shaped epibranchial carapace 
ridge; and the posterior border of the arm of the cheliped bearing 
two distinct spines instead of one and a doubtful second. 
Portunus argentatus (A. Milne Edwards) 
FIGURE 2 
Amphitrite argentata White, 1847, p. 146 (descriptio nulla). 
Neptunus argentatus A. Milne Edwards, 1861, pp. 332, 339, pl. 31 (figs. 4, 4a, 4b). 
Portunus (Achelous) argentatus (A. Milne Edwards).—Rathbun, 1906, p. 871.— 
Edmondson, 1954, pp. 238-239, figs. 14, 15. 
Portunus argentatus (A. Milne Edwards).—Stephenson, 1961a, pp. 105-106, figs. 
1F, 3D, pls. 2 (fig. 2), 4D, 5A.—Crosnier, 1962, pp. 50-51, figs. 71, 75, 77, 
80, 81, pl. 3 (fig. 1). 
Matrriau.—As indicated below, two forms are distinguishable in 
adult males, designated forms A and B respectively. These are listed 
separately, as are females and juveniles. 
