426 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



Family POECILIIDAE : Top Minnows 



This family is naturally restricted to temperate and tropical waters 

 of the Western Hemisphere. Its inclusion in the present catalog is 

 based on the introduction of the following species into Thailand : 



Genus GAMBUSIA Poey 



Gambtisia Poey, Memorias sobre la historia natural de la isla de Cuba, vol. 1, 

 p. 382, 1854. (Type, Oamhusia punctata Poey.) 



GAMBUSIA HOLBROOKII (Girard) 



Heterandria holbrookii Girakd, 1859, p. Gl (Charleston, S. C). 

 Gambusia holirooki Smith, 1029, p. 14 (Siam, introduced). 



This well-known and well-tested destroyer of mosquito larvae, 

 native to the coastal waters of the United States from New Jersey 

 southward, was introduced into Thailand in 1929 from Palestine, where 

 the fish had been taken in 1922 from Augusta, Ga. From a single small 

 lot brought into Thailand by Mrs. Emily J. Collins, many thousands 

 have resulted, and numerous waters in the Bangkok region, in Eastern 

 Thailand and in other parts of the country have been stocked. 



The females reach a maximum length of about 5 cm., and the males 

 2 to 2.5 cm. Frequent broods are produced throughout the year, and 

 in protected waters a very large number may result from a single pair 

 in a short time. The young, about 0.8 cm. long at birth, swim actively 

 as soon as they are born. 



Orcier Synentognathi : Gars and Half beaks 

 Family BELONIDAE : Gars 



The gars inhabit temperate and tropical waters in all parts of the 

 world, and are much more prominent in the sea than in rivers and 

 lakes. Some of the marine species have a tendency to ascend rivers, 

 and some entire genera are restricted to fresh water. 



These fishes may be recognized easily by their long and slender 

 bodies, by the prolongation of their jaws into a beak armed with rows 

 of sharp opposing teeth, and by the insertion of the dorsal and anal 

 fins opposite each other in the posterior fourth of the length. Besides 

 a number of species, some of large size, in the coastal waters of Thai- 

 land, there are two genera represented in rivers and lakes often far 

 from the sea : 



la. Second, third, and fourth pairs of upper pharyngeal bones tooth-bearing; 



lower pharyngeal bone with a median tonguelike patch Strongylura 



1?». Only third pair of upper pharyngeal bones tooth-bearing; lower pharyngeal 



bone with a median elliptical patch Xenentodon 



Genus STRONGYLURA van Hasselt 



Stronffylura Hasselt, Alg. Konst. Letterbode, vol. 2, p. 130, 1823. (Type, Strongy- 

 lura caudimaculata van Hasselt=.Betone strongylura van Hasselt.) 



