FRESH-WATER FISHES OF SIAM, OR THAILAND 337 



Genus OMPOK Lacepede 



Ompok Lacepede, Hisloire naturelle des poissons, vol. 5, p. 49, 1803. (Type, 

 OmpoJc siluroides Lacepede.) 



The generic name Ompok^ given and defined by Lacepede in 1803, 

 with a designated species {siluroides) ^ unquestionably supplants Gal- 

 lichrous of Hamilton, 1822. Bleeker (1862 (301) , vol. 2, p. 85) appears 

 to have been largely responsible for the substitution of the later for the 

 earlier name. This action, followed by most of the later authors, was 

 based on the wholly untenable ground that the name "rested on an error 

 and was only a mutilated reproduction of the Malay name Limfoh?'' 



Lacepede's diagnosis of Ompok leaves much to be desired. The 

 specimen on which the genus was based was dried and very badly 

 preserved ; the accompanying drawing was faulty ; and the description 

 erroneously stipulated the absence of a dorsal fin, which was over- 

 looked. More than 30 years later Valenciennes (Cuvier and Valen- 

 ciennes, 1839, vol. 14, p. 362) reexamined Lacepede's type specimen and 

 discovered the dorsal fin. 



The fact that a genus is inadequately or even incorrectly described 

 does not affect the validity of the proposed name if it otherwise con- 

 forms to the requirements of zoological nomenclature. In this case, 

 with a single recognizable species designated and described, and with 

 the principal defect in the original description subsequently rectified by 

 a reexamination of the type, Ompok clearly leaves no room for Cal- 

 lichrous (Hamilton, 1822), which was not diagnosed or defined by 

 Hamilton and was first defined by Swainson (1839, p. 306). In 1862 

 Bleeker, (1862 (301), vol. 2, p. 17) redefined Ccdlichrous and desig- 

 nated as its tyj)e pabda of Hamilton, a synonym of Lacepede's siluroides 

 (which in turn was equivalent to Bloch's Silurus himaculatus, 1797). 



OMPOK BIMACULATUS (Bloch) 



FlGtTEB 77 



Silurus himaculatus Blooh, 1797, vol. 11, p. 17, pi. 364 (Malabar). 



Callichrous bitnaculatus Bleeker, 1865 (356), p. 175 (Siam). — Peters, 1868, 



p. 271 (Siam). — Weber aud de Beaufort, 1913, vol. 2, p. 209 (Siam). — Hoba, 



1923b, p. 165 (Nontaburi). 

 Ompok himaculatus Fowleb, 1935a, p. 96 (Bangkok). 



The range of this species extends from Java, Borneo, and Sumatra 

 to Malaya, Thailand, and Indo-China, and thence to Burma, India, 

 and Ceylon. In Thailand the fish is widely distributed and abundant 

 in the central plain, the Peninsula, and in Southeastern and Eastern 

 Thailand. Waters from which specimens have been examined and 

 preserved are: Central Thailand (Menam Chao Phya at Paknam, 

 Bangkok, Nontaburi, and Paknampo; Menam Sak at Dha Luang; 



