FRESH-WATER FISHES OF SIAM, OR THAILAND 427 



STRONGYLURA STRONGYLURA (van Hasselt) 



Belone strongylwa van Hassext, 1823, p. 130 (Java). 

 Mastacembelus caudimaciila Bleekeh, 1865 (356), p. 176 (Siam). 

 Tylosurus strotigylurua Weber and de Beaufokt, 1922, vol. 4, p. 121 (Siam). 

 Strongylura strongylura Fowlek, 1934a, p. 144 (Bangkok, Chiengmai) ; 1935a, 

 p. 130 (Bangkok, Paknam, Khao Nam Poo) ; 1939, p. 75 (Trang). 



This is the only member of the genus regularly entering the fresh 

 waters of Thailand. The species, of wide distribution in the Pacific 

 and Indian Oceans, and primarily marine and estuarine, has been col- 

 lected in the inner lake of the Tale Sap and in the Tale Noi in the 

 Peninsula, in the lower reaches of the Menam Chao Phya, in the Meyom 

 at Mepoon, in the Menam Sak at Khao Nam Poo, and in the Meping 

 at Chiengmai. 



The fish attains a length of 45 cm. Two fishes 27.5 and 34.5 cm. long, 

 taken August 23, 1929, in the fresh flood water off the mouth of the 

 Menam Chao Phya, were females with asymmetrical ovarian develop- 

 ment : the right ovary in each fish contained nearly ripe eggs, the left 

 ovary was less than half the size but with well-formed eggs, which 

 would doubtless have been expelled at a second spawning time. 



The vernacular name, shared with other members of the family, is 

 pla hatung heo. A variation heard in the inner lake of the Tale Sap 

 at Pak Bhayoon is pla ^tung kwai. 



Genus XENENTODON Regan 



Xenentodon Began, Ann. Mag. Nat. Hist., ser. 8, vol. 7, p. 332, 1911. (Type, 

 Belone cancila Hamilton.) 



The gars of this genus are of strictly fresh-water habitat in India, 

 Burma, Ceylon, Thailand, Malaya, Borneo, Sumatra, and probably 

 French Indo-China (Cambodia). Two closely related forms are re- 

 corded from Thailand waters. 



la. Scales in lateral line about 250 ; depth of body 1.5 times its width and contained 

 8 to 12 times in distance from tip of upper jaw to midbase of caudal fin ; 

 distance of dorsal origin from midbase of caudal contained 5.S times in 

 total length cancila 



16. Scales in lateral line 200 to 220 ; depth of body equal to its width and contained 

 14 to 18 times in distance from tip of upper jaw to midbase of caudal fin ; 

 distance of dorsal origin from midbase of caudal contained 4.8 times in 

 total length canciloides 



XENENTODON CANCILA (Hamilton) 



Esox cancila Hamilton, 1822, pp. 213, 380, pi. 27, fig. 70 (Gangetic provinces). 

 Mastacembelus cancila Bleeker, 1865 (347), p. 35 (Siam) ; 1865 (356), p. 176 



(Siam). 

 Belone cancila PeJters, 1868, p. 272 (Siam). 

 Xenentodon cancila Hora, 1923b, p. 175 (Bangkok) ; 1924a, p. 471 (Tale Sap). 



From India, Ceylon, and Burma the range of this species extends 

 through Thailand to Malaya. Kecords for Thailand are the Menam 



