FRESH-WATER FISHES OF SIAM, OR THAILAND 437 



the families Synapturidae and Cynoglossidae, which locally have many 

 salt-water forms also. Both these families are included in the 

 Soleidae by Weber and de Beaufort (1929, vol. 5), while Norman 

 (1928) places the Synapturidae in the Cynoglossidae. The arrange- 

 ment here followed is that of Jordan (1923). The somewhat differ- 

 ent treatment of this matter by various authors is of no great impor- 

 tance, and represents simply individual opinion as to the taxonomic 

 value of certain characters. In the Cynoglossidae the eyes are on 

 the left side and pectoral fins are lacking; in the Synapturidae the 

 eyes are dextral and pectoral fins are present (although not fully 

 developed in all examples) in one local genus and absent in the other. 

 There is a deep-seated and widespread belief in Thailand that the 

 soles of the genera Synaptura and Cynoglossus attach themselves to 

 the bottom of boats and there make musical sounds. This belief per- 

 sists from generation to generation and loses little strength with the 

 passage of the years, notwithstanding that no one has ever seen a sole 

 attached to either a stationary or a moving boat, and no one has ever 

 observed the fish while making musical or other sounds either in or 

 out of the water. The basis for this belief, and the explanation of 

 the sounds wrongly attributed to soles, were discussed at some length 

 by the writer (1927b). 



Family SYNAPTURIDAE: Soles 



The two local genera are distinguished chiefly by the presence or 

 absence of pectoral fins, as follows : 



la. Pectoral fins present Synaptura 



11). Pectoral fins wholly absent Achiroides 



Genus SYNAPTURA Cantor 



Synaptura Cantor, Jouru. Asiat. Soc. Bengal, vol. IS, p. 1204, 1850. (Type, 

 Pleuronectes commcrsonianl Lacepede. ) 



Small right-sided soles inhabiting both salt and fresh waters. Four 

 local fresh-water species are recognized as follows : 



la. Color of blind side whitish or yellowish. 

 2a. Pectoral fins well developed, right pectoral as long as ventrals and 3 times 

 diameter of eye ; dorsal rays 61 to 65, anal rays 44 to 50 ; scales in lateral 



line 75 to 85 orlentalis 



26. Pectoral fins rudimentary, right pectoral about as long as diameter of 

 eye. 



3a. Dorsal rays 48, anal rays 38; scales in lateral line 54 harmandi 



^h. Dorsal rays 81 to 83, anal rays 63 ; scales in lateral line 110— panoides 



lb. Color of blind side reddish brown ; pectoral fins rudimentary ; dorsal rays 54, 



anal rays 45; scales in lateral line 66 aenea 



590087 — 45 29 



