FRESH-WATER FISHES OF SIAM, OR THAILAND 63 



2&. Snout scaleless or scaly ouly at sides. 

 3a. A preorbital spine. 

 4a. Dorsal spines more than 30, dorsal soft rays 60 to 90. 



5a. Dorsal rays XXXIV to XXXIX, 79 to 90 ; anal rays III, 79 to 90. 

 6a. Body rich brown above ; a blackish zigzag band extending from eye 

 to base of caudal fin, sending branches to dorsal and anal 



flns armatus arinatiis 



65. Body covered with dark brown or black reticulations enclosing large 

 round or oval pale spots ; finer reticulations may cover abdomen ; 

 vertical fins dark, a dark spot at base of pectoral. 



armatus f avus 



5&. Dorsal rays XXXII to XXXIV, 60 to 75 ; anal rays III, 56 to 75 ; 



body brown, with white lines and several rows of small white 



spots ; bases of vertical fins blackish, margins white ; a black spot 



at base of pectoral argus 



4b. Dorsal spines less than 30, dorsal soft rays 41 to 56. 



7a. Doi-sal rays XXIX, 46; anal rays III, 56; back and sides brown, 

 under surface yellowish; body with about 18 dark brown cross 

 bands which do not reach midline of back under spinous dorsal fin 



and extend to edge of anal fin circumcinctus 



76. Dorsal rays XXVI to XXVIII, 45 to 48; anal rays III, 41 to 43; 

 back and sides brown, under surface white; body with 16 to 20 

 irregular blackish cross bands which extend entirely across body 



and do not reach edge of anal fin taeniagaster 



36. No preorbital spine; dorsal rays XXXII to XXXVII, 70 to 80; anal 

 rays III, 70 to 80 ; body black or brown, with 4 longitudinal red bands ; 



vertical and pectoral fins black, with red margin erythrotaenia 



16. Dorsal and anal fins not confluent with caudal ; no preorbital spine ; dorsal 



rays XVI, 46 to 48 ; anal rays III, 42 to 45 ; body with 18 or 19 dark cross 



bands inclined downward and forward, a narrow dark stripe in inter- 



. spaces paucispinis 



MASTOCEMBELUS MACULATUS Cnvier and Valenciennes 



Mastacemhelus maculatus Cuviee and Vaxenciennes, 1831, vol. 8, p. 461 



(Molucca). 

 Macrognathus maculatus Bleeker, 1865 (356), p. 174 (Siam). 



Only Bleeker has recorded this species from Thailand. It is other- 

 wise known from Java, Borneo, Billiton, and Sumatra. The chief 

 features are the completely scaly snout (not found in any other local 

 form), the presence of a preorbital spine but no preopercular spines, 

 the extension of the mouth to a point under the posterior nostril, and 

 a clouded brown body, yellow margins to the vertical fins, and a series 

 of black spots along the base of the dorsal fin. 



MASTOCEMBELUS ARMATUS ARMATUS Gunther 



Mastacembelus armatus var. armata Gunther, 1861, vol. 3, p. 543 (Siam; Cal- 

 cutta; East Indies). 



Macrognathus armatus Bleekee, 1865 (356), p. 174 (Siam). 



Mastacembelus armatus von Martens, 1876, p. 396 (Bangkok). — Sauvagb, 1881, 

 p. 160 (Siam).— Fowler, 1934a, p. 146 (Chiengmai). 



The range of this fish extends from India and Ceylon to southern 

 China, and thence through Thailand and Malaya to Sumatra. The 



