286 BULLETIN 18S, UNITED STATES NATIONAL MUSEUM 



GYRINOCHEILUS PENNOCKI (Fowler) 

 Gyrinocheilops pennocki Fowler, 1937, p. 161, tigs. 98, 99 (Mekong at Kemarat). 

 Described from a specimen 14.5 cm. long, with a paratype 7.8 cm. 

 long, this fish is known only from the Mekong at Kemarat in Eastern 

 Thailand. The species is very similar to G. kaznakovi Berg, from 

 which it may differ in having the eye placed near the midlength of 

 the head and in the presence of 10 branched rays in the dorsal fin. 

 The position of the eye, however, in ayjnonieri varies with age, being 

 more advanced in the young ; and in a few examples the branched dor- 

 sal rays have been found to number 10. The proportions, squamation, 

 and general pattern of body coloration are the same in the two forms. 

 A reported color difference is the absence in the present species of a 

 dark spot immediately posterior to the inhalent gill-opening, which 

 is characteristic of aymonieri. 



Family COBITIDAE: Loaches 



This strictly Old World family is well represented in Thailand. 

 Most of the species are of small size and they frequent mountain 

 streams; a few are found in larger rivers, and some occur even in 

 lakes. Of the eight genera so far detected in Thailand, six have 

 a wide distribution in India, Burma, Malaya, Indo-China, China, and 

 the East Indian Archipelago, and two are peculiar to Northern Thai- 

 land. 



The loaches are of little commercial importance. Some of the 

 larger forms (such as certain species of Botia) are seen in the markets 

 of the more populous communities. Nearly all the species are eaten 

 by the country people, especially in the mountainous districts. 



Fishes of most of the species are protected from danger by burying 

 themselves, sometimes with great rapidity, in the sand or gravel of 

 stream bottoms, and most of them enjoy some immunity from capture 

 by snakes, water lizards, birds, and other fishes owing to a pair of erec- 

 tile suborbital or preorbital bony spines, which may be locked firmly 

 in position. 



The following characters will differentiate the species : 



la. An erectile spine arising from etlimoid bone and concealed in a groove 

 under or before each eye. 

 2a. Form oblong ; eyes not covered with skin ; a bifid spine below and partly 

 before eye; origin of dorsal fin over or in advance of base of ventral 



tins; 3 pairs of barbels (2 rostral, 1 maxillary) Botia 



2&. Form elongate ; eyes covered with skin. 



3a. Origin of dorsal fin before, over, or very slightly behind base of ventral 

 fins ; head with or without scales ; 3 or 4 pairs of barbels. 

 4a. Head partly scaled; barbels 4 rostral, 2 maxillary, 2 mandibular; 

 caudal fin truncate or slightly emarginate Lepidocephalus 



