32 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
Neptunus (Achelous) orbitosinus (Rathbun).—Gordon, 1938, pp. 182-185, figs. 
5a-g, 6c, 6d (including N. octodentata). 
Neptunus (Achelous) orbitospinus (Rathbun).—Sakai, 1939, p. 396, pl. 81 (fig. 2). 
Portunus orbitosinus Rathbun.—Stephenson and Campbell, 1959, pp. 113-114, 
figs. 2L, 3L, pls. 3 (fig. 4), 4L, 5L.—Stephenson, 196la, pp. 108-109.— 
Crosnier, 1962, pp. 55-57, figs. 88, 90-91, 93.—Miyake, Sakai, and Nishi- 
kawa, 1962, p. 128 (record only). 
b 
Ficurr 6.—Portunus orbitosinus Rathbun, male pleopods and abdomens, respectively. 
Three variants of form A: a and e, Philippines, Mariveles, No. 27, Reese; b and f, Philip- 
pines, Sta. 5158, Alb.; c and g, same asa ande. Form B: d and h, Philippines, Labuan 
Blanda I., 4/b. (Scales=a-d, 1 mm.; eh, 5 mm.) 
MarrrraL.—Two forms are recognized in adult males, called forms 
A and B, respectively. These are listed separately as are females. 
MALES (FORM A) 
Philippines: Subig Bay, China Sea off southern Luzon, shore, 
