NO. 3500 PORTUNID CRABS — STEPHENSON AND REES 13 



Remarks. — Because two forms of male pleopods have been de- 

 scribed for this species (Stephenson and Rees, 1967, p. 16), pleopods 

 of all the males in the present collection were examined. The number 

 involved (almost 1500) no doubt greatly exceeds the numbers ex- 

 amined in any other species of portunid and possibly any other 

 brachyuran. 



All males were concluded to belong to form B, which typically 

 possesses a pleopod with a right-angled bend. The range of the 

 present material clearly links the shapes figured by Crosnier (1962, 

 fig. 77) and by Stephenson and Rees (1967, fig. 2), with the bulk 

 being intermediate. 



A very small number of indi^iduals (not more tlian five) possessed 

 pleopods ^^ith considerable curvature near their right-angled bends 

 (fig. 2a, this paper). A greater number (33) possessed relatively 

 straight pleopods (fig. 26). The latter were relative^ small specimens 

 (breadths 15-ca. 21.5 mm) although they overlapped considerably 

 the sizes of those with normal pleopods (breadths 17.5-40 mm). It 

 is assumed that the small specimens were immature males, which 

 would have developed curved pleopods on later moults. 



In addition to variations in curvature, there were variations in 

 the form and spinulation of the tips of the pleopods (see figs. 2e-g). 

 While none showed the bulbous shape of form A (Stephenson, 1961, 

 figs IF, 3D), one specimen showed slight swelling and reasonably 

 dense spinulation (figs. 2c, (j). 



A single specimen from Station AB 21-63 was unsexable because 

 of presumed parasitic castration caused by parasites in both branchial 

 cavities. Three specimens witli parasites in a single branchial cavity 

 were noted (two with left cavities, one with right, all from Station 

 AB 21-63). In none of these specunens was the sex indeterminable 

 (two females, one male). Four ^Soccwiwa-infested specimens were 

 noted. Two of these were clearly males, with normal pleopods, 

 ^\'hile twt) were most probably females. Sacculina infestation had 

 less obvious effects upon secondary sexual characteristics than had 

 the double branchial infestation. 



Distribution. — East coast of Africa to Japan, Australia, and 

 Hawaii. 



Portunus emarginatus Stephenson and Campbell 



Porlunus emarginalus Stephenson and Campbell, 1959, pp. 107-8, figs. 2H, 3H, 

 pi. 2 (fig. 4), pis. 411, 511.— Crosnier, 1962, pp. 66-8, figs. 108, 112-4, 116, 

 120, 121. —Stephenson and Rees, 1967, p. 30. 



IPortunus longispinosiis Rathbun. — Stephenson and Campbell, 1959, pp. 104-6, 

 figs. 2F, 3F, pi. 2 (fig. 2), pis. 4F, 5F. 



Material examined. — 1 male (10.5 mm), Sta. No. B9. 

 Dredged, 18-24 ft., fine white sand. 



