CRUSTACEA OF THE MERGUI ARCHIPELAGO. 261 
the end of the terminal segment measures about 27 centim. The 
hands are nearly equal in shape and size, and the cardiac region 
is armed with some spines. 
Thalassina anomala has been recorded from the Nicobar Islands, 
Java, Borneo, the Philippine and Fiji Islands. 
Family ScYLLARIDS. 
Genus THEnvs, Leach. 
146. THENUs oRIENTALIS, Fabr. 
Seyllarus orientalis, Fabricius, Suppl. Entom. p. 399. 
Thenus orientalis, Milne-Edwards, Hist. Nat. des Crustacés, p. 286; 
Desmarest, Considérations sur la Classe des Crustacés, pl. xxxi. fig. }. 
Five specimens were collected in the Mergui seas. 
Thenus orientalis inhabits the Indian Ocean. 
Family ALPHFIDE. 
Genus ALPHEUS, Fubr. 
147. ALPHEUS BREVIROSTRIS, Oliv. 
Paleemon brevirostris, Olivier, Encyclop. Méthodique, t. viii. p. 664, 
pl. 319. fig. 4. 
Alpheus brevirostris, Milne-Edwards, Hist. Nat. des Crustacés, t. ii. 
. 300. 
: Alpheus malabaricus, Hilgendorf, Monatsber. d. k. preuss. Akad. d. 
Wiss. Berlin, Nev. 1878, p. 832 (nec Alpheus malabaricus, de Haan). 
An adult specimen was collected at Elphinstone Island, and a 
young one in King Island Bay. 
This species is most closely allied to Alpheus malabaricus 
(Fabr.), de Haan, and A. Kingsleyi, Miers, both from Japan. 
These three species form a small section of the genus, which 
may be distinguished from the other species of Alpheus with a 
spiniform rostrum, rounded ocular hoods, and having the basal 
joint of the outer antenne without an external spine, by the 
upper margin of the larger hand being notched, and by the 
lower being entire. Mr. Kingsley is wrong in uniting A. rapax 
(Fabr.), de Haan, to this section, as in it both margins of the 
larger hand are entire. 
