50 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



not uncommon in Thai waters, and many examples were examined and 

 a number of specimens preserved from points about the head of the 

 Gulf of Siam. It is to be found chiefly in salt water, but it enters 

 estuaries, such as the Chantabun Estuary in Southeastern Thailand, 

 and shows a tendency to venture short distances up streams like the 

 Bangpakong and the Menam Chao Phya. 



It reaches a length of 20 cm., but owing to its boniness and limited 

 amount of muscular tissue it has little food value. 



This species is known to the fishermen as pla hang (compressed fish) , 

 pla hat mai (bamboo-leaf fish) , and pla ijyitt, a name sometimes shared 

 with Pellona. 



Subfamily Dorosomatinae : Gizzard Shads ; Mud Shads 



This subfamily is given full family rank by Jordan (1923). There 

 are two local genera, distinguished as follows: 



la. Last dorsal ray produced as a filament, which reaches caudal fin ; maxillary 

 with its posterior end expanded and curved downward ; gill rakers very nu- 

 merous (about 140) Nematalosa 



1&. Last dorsal ray not produced as a filament ; maxillary with its posterior end 

 straight and tapering, its median part expanded ; gill rakers less numerous 

 (about 80) Anodontostoma 



These fishes in Thailand, like their close relatives {Dorosoma of 

 Rafinesque) in the Atlantic, are migratory, primarily marine but enter- 

 ing fresh or brackish waters to spawn. They subsist chiefly on minute 

 organic objects or particles obtained in bottom mud, which is strained 

 by their numerous fine gill rakers. Digestion is facilitated by a long 

 convoluted intestine beset with fingerlike villi and supplemented by 

 caeca, which pour juices into the intestine; and by a thick-walled 

 stomach like the gizzard of a fowl. 



Genus NEMATALOSA Regan 



Nematalosa Kexjan, Ann. Mag. Nat. Hist., ser. 8, vol. 19, p. ai3, 1917. (Type, 

 Clupea nasus Bloch.) 



NEMATALOSA NASUS (Bloch) 



Clupea nasus Bloch, 1795, vol. 9, p. 116, pi. 429, fig. 1 (Malabar). 



This species of the Indo-Australian Archipelago and India occurs 

 throughout the Gulf of Siam and ascends streams for short distances. 

 There are no published references to its occurrence in the fresh waters 

 of Thailand, but it has been observed in such situations on various occa- 

 sions. A favorite resort and spawning ground is the Tale Sap, where, 

 in the inner lake, it has been found in July and October. Fish of both 

 sexes with sexual organs in an advanced stage of development but not 

 in actual spawning condition were collected in October. 



Adult fish are 16 to 20 cm. long. 



