530 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



first applied to the fish was preoccupied for a Japanese species that 

 was the type of the genus Rhinogobius. 



ACENTROGOBIUS CYANOMOS (Bleeker) 



OoHus ci/anowos Buekkek, 1849 (15), p. 25 (Surabaya, Kammal). 

 Acentrogohws spiloptcrns Smith, 1932a, p. 259, pi. 23, fig. 2 (Tachin River). 

 Acentrof/obiiis cyanomos Koumans, 1937b, p. 178 (Tachin River). 

 Gohius cyanosmos Fovs^LEai, 1939, p. 53, (Krabi). 



The range of this goby covers the Indo-Australian Archipelago and 

 extends to the northern shores of the Gulf of Siam, where it is 

 abundant in places. 



The second and third dorsal spines are usually elongated and fili- 

 form, and the second spine may extend beyond the base of the second 

 dorsal fin or even to the caudal. This feature, which is characteristic 

 of the male, is combined with peculiar coloration: The green back 

 and sides have each scale with a spot of pearly blue, a large round spot 

 at the upper angle of the gill opening is blue-black, and the very dark 

 second dorsal and caudal fins have rows of white spots on the inter- 

 radial membranes. 



The maximum length of local female specimens so far recorded is 

 11.5 cm., the males being larger. A female, 8.2 cm. long, taken in the 

 Tachin River in December contained nearly ripe eggs. 



The nominal species A. spilopterus was considered by Koumans as 

 agreeing with A. cyanomos^ to the types of which he had access in the 

 Leiden Museum, and this conclusion of Komnans is accepted. 



The vernacular name is pla hu. 



ACENTROGOBIUS OLIGACTIS Bleeker 



Acentrogohius oUgactis Bi^ekeb, 1875 (461), p. 132 (Singapore). 



Described in 1875 from three specimens, 4.1 to 4.8 cm. long, taken 

 at Singapore, this species has rarely been observed since. It is pos- 

 sible to record it from Southeastern Thailand on the basis of a speci- 

 men, 3.8 cm. long, taken on the shore of Koh Chang on April 15, 1925, 

 and another specimen, 4 cm. long, taken on Koh Kut on May 25, 1929. 

 Both of these specimens were examined and identified by Dr. F. P. 

 Koumans with Bleeker's types at hand. 



ACENTROGOBIUS CHLOROSTIGMATOIDES (Bleeker) 

 Gobius chlorostigmatoides Bleeker, 1849 (15), p. 26 (Surabaya and Kammal). 



This little goby of Java, Borneo, and other East Indian islands is 

 represented in the collection of the U. S. National Museum by five 

 specimens, 4.3 to 6.9 cm. long, taken by the writer in the Bangpakong 

 River, Central Thailand, June 26, 1933; one, 5.1 cm. long, from the 



