FRESH-WATER FISHES OF SlAM, OR THAILAND 293 



A specimen, 19.2 cm. long, from the headwaters of the Menam Mun 

 at Pakjong, June 21, 1934, has the body marked with numerous dark 

 spots tending to form longitudinal lines, the dorsal and anal fins 

 marked as in the type but the caudal is plain; the dorsal fin, with 

 nine branched rays, arises appreciably in advance of the ventrals. 

 The fish is a female with nearly ripe eggs, the ovaries being 6 cm. 

 long. 



The nearest relative is B. 'berdmorei as described and figured by 

 Day, which shows a number of differences in form and color: there 

 are 11 to 13 branched dorsal rays (instead of 9 as in B, hecmforti)^ 

 the origin of the ventral is slightly in advance of that of dorsal (in- 

 stead of considerably behind), there are 10 or 11 dark cross bands 

 from back to abdomen (instead of none), and there are no parallel 

 dark stripes on the back anteriorly. 



Fowler (1934a) thought B. heauforti synonymous with B. Kymeno- 

 pJtysa but later (1937) revised that opinion. 



The local people call it pla mu and say it gets to be about 25 cm. 

 long. 



Genus LEPIDOCEPHALUS Bleeker 



Lepidocephalus BleetivEr, Nat. Tijdschr. Neclerl.-Indie, vol. 16, p. 303, 1858-59. 

 (Type, Coxitis tnacrocMr Bleeker.) 



The lepidocephalids are small fishes found mostly in swift brooks 

 but also in swamps and lakes. They appear to prefer sandy or fine 

 gravelly bottom, into which they are able to burrow and quickly 

 disappear, if alarmed or frightened. According to Day, the spinous 

 first pectoral ray helps in "digging in." 



The local species may be distinguished as follows : 



la. Scales in lateral line about 100 or more. 

 2a. Caudal fin truncate. 



3a. Depth of caudal peduncle equal to or less than its length ; back and side 

 with small dark brown patches of irregular shape, sometimes forming 

 a row along, side ; a round black spot at upper part of caudal base ; 

 all fins sometimes with transverse rows of dark spots on rays, the 



spots sometimes confined to dorsal and caudal octocirrhus 



3&. Depth of caudal peduncle greater than its length ; side with a row of 

 12 to 15 dark spots ; a broad median dark band from occiput to dorsal 

 fin ; a black spot at upper part of caudal base ; dorsal and caudal fins 



with 6 or 7 transverse rows of dark spots on rays cataractus 



26. Caudal fin emarginate; side with a well-defined dark longitudinal stripe 



connecting dark spots berdmorei 



\h. Scales in lateral line about 72; body with 10 to 12 rather obscure brown 

 saddles ; a small black spot at base of first dorsal rays ; a dark brown 

 stripe along side from head to caudal base ; dorsal fin with transverse 

 rows of dark spots on rays ; caudal fin with 6 or 7 transverse rows of 

 dark streaks taeniatus 



590087—45 20 



