34 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
general facies. Four main variants were noted and are figured 
(fig. 6). In the first, the pleopod is short and stout, little curved and 
naked on the center of its outer surface. In the second, the appendage 
is relatively thinner, more curved, and with hairs in the center of its 
outer surface. In the third, the appendage is even more curved but 
otherwise resembles the second form. In the fourth, the appendage 
is very long and slender, slightly curved, and resembles Gordon’s 
specimen from the “Challenger” collection. 
The first three variants show a certain amount of intergrading and 
are concluded to belong to the same morphological entity, whether a 
species, subspecies, or “form.” What Stephenson and Campbell 
considered “inconceivable variation” apparently occurs. On the 
other hand, there seems to be a distinct hiatus between these and the 
fourth variant. Following the pattern established for P. argentatus, 
the first three variants are designated form A and the fourth, form B. 
Crosnier (1962) figured a male pleopod of P. orbitosinus from 
Madagascar, greatly resembling figure 6 (c). Most of the present 
specimens differ from Crosnier’s in having a larger first anterolateral 
tooth well separated from the second tooth. All differ in having 
smaller ninth teeth pointing less directly outward. 
DistTRiBuTION.—Seychelles to Japan, and Australia. 
Portunus pelagicus (Linnaeus) 
Ficures 12c,d, 17b 
Cancer pelagicus Linnaeus, 1766, p. 1042. 
Neptunus pelagicus (Linnaeus).—Alcock, 1899, p. 34.—Sakai, 1939, pp. 387-388, 
pl. 49. 
Lupa pelagica (Linnaeus).—Barnard, 1950, pp. 152, 153-154, fig. 27. 
Portunus pelagicus (L.).—Stephenson and Campbell, 1959, pp. 96-98, figs. 2A, 
3A, pls. 1 (fig. 1), 4A, 5A.—Sankarankutty, 1961a, pp. 103-104.—Crosnier, 
1962, pp. 43-44, figs. 58, 61, 67.—Miyake, Sakai, and Nishikawa, 1962, 
p. 128 (record only). Dell, 1964a, pp. 303-304, 2 figs. 
Mareriau.—Malay Archipelago: Tachalorn, Siam, July 24, 1923, 
H. M. Smith, 1 male; Bangkok, Siam, July 24, 1923, H. M. Smith, 
1 female; off Paknam, Gulf of Siam, Sept. 8, 1923, 1 female; Gulf of 
Siam, Lang Suen, Sept. 17, 1923, H. M. Smith, 1 female; Bandon 
Bight, Siam, September 1923, H. M. Smith, 1 male, 1 ovig. female; 
Chantabun River, at Lem Sing, Siam, May 7, 1927, H. M. Smith, 
1 female; Singapore, Mar. 14, 1934, Herre, 1 female; Sta. 1004, 
purchased from Thailand, received Aug. 24, 1955, R. E. Elbel, 2 males, 
1 female; Sta. 27, east coast of Gulf of Thailand, S. of Trat Bay off 
Lam Son Village, near Cambodian border, 11°57/00”N., 102°44’45”E., 
10 m., shrimp trawl, Oct. 29, 1957, GVF, 1 male; Thailand, 
Songkhla, channel between Songkhala City and Goh Gnu I., Nov. 3, 
1957, GVF, 1 female. 
| 
