436 BULLETIN 18 8, UNITED STATES NATIONAL MUSEUM 



the grasping by one fish of the pectoral or caudal fin of the other, and 

 the closing of the jaws either straight or obliquely across the body. 



Only rarely is any injury done to either combatant. The lower jaw, 

 perhaps inadvertently used for stabbing, may occasionally draw blood 

 from the gills. The tip of the lower jaw may very exceptionally be 

 broken. Very rarely one or both fishes, without having sustained any 

 apparent injury, may die after being separated. The contest, in the 

 great majority of cases, is ultimately decided by the ability of one fish 

 to maintain, and, after a breakaway, to regain an advantageous hold 

 that will cause exhaustion or affect the stamina. With evenly matched 

 fish in a long-drawn-out struggle, determination of the victor may have 

 to be based on points rather than on a single decisive act. Ordinarily 

 the climax is reached when one fish shows unwillingness or inability to 

 lock jaws with the other. 



Phya Akaraja Varadhara, former Thai minister to Washington and 

 London, on the conclusion of his long diplomatic career devoted him- 

 self for many years to the cultivation of Dermoge7iys at his Bangkok 

 residence, and made interesting observations of the breeding, growth, 

 and wrestling qualities of the species. One noteworthy observation, 

 which should be confirmed by zoologists, indicated that virgin females 

 may under certain conditions produce a limited number of young 

 without ever having been associated with males. 



The position of the ventral fins with reference to the gill openings 

 and the base of the caudal fin seems to be subject to considerable 

 variation. Weber and de Beaufort said of the ventrals, "their base 

 a little nearer to caudal than to branchial openings," and Bleeker's 

 figure (Atlas, 1866-72 [301], vol. 6, pi. 253, fig. 2) agrees with that 

 description. The form called Dermogenys siamensis by Fowler, based 

 on the more anterior insertion of the ventrals, appears to be referable 

 to the present species. While the figure of the type of D. siameiisis^ a 

 specimen 69 mm. long, apparently a female, from Chiengmai, shows the 

 ventral base midway between the midbase of the caudal fin and the 

 anterior margin of the eye. Fowler's figure of another specimen of 

 the same form, a male 36 mm. long, from Bangkok, represents the 

 ventral base as nearly midway between the caudal base and the gill 

 opening. 



In allusion to its long, slender lower jaw, this fish is called pla khem 

 (needle fish) by the Thai. In allusion to its characteristic habit, 

 it was dubbed wrestling fish by the present writer after search for a 

 distinctive English name. 



Order Heterosomata : Soles and Flounders 



This world-wide order has many genera and species in Thailand 

 waters. All the forms that regularly inhabit fresh water belong in 



