FRESH-WATER FISHES OF SIAM, OR THAILAND 503 



36. Vomer without teeth. 



4a. Head with bony crests in interorbital space and around eyes; scales 



in longitudinal series 26 to 30 ; a large black spot at base of pectoral 



fin with two small white (pink) spots in the anterior part of the 



black spot. 



5a. Head long, pointed, its depth equal to its breadth ; lower jaw strongly 



projecting ; supraorbital ridge low and smooth or nearly so_ Butis 



5b. Head short, obtuse, its depth less than its breadth ; lower jaw very 



slightly or not projecting; supraorbital ridge strongly serrated. 



Prionobutis 

 4&. Head without bony crests in interorbital space and about eyes. 

 6a. Canine teeth absent. 



7a. Scales in longitudinal series 30 to 40 ; branched rays in dorsal and 



anal fins 7 to 9 Ophiocara 



76. Scales in longitudinal series 60 to 90 ; branched rays in dorsal and 



anal fins 8 to 10 Oxyeleotris 



66. Canine teeth present. 



8a. Lower jaw with one or several pairs of posterior canine teeth ; 

 scales ctenoid, 70 to 110 in longitudinal series ; branched rays of 



dorsal and anal fins 11 to 18 Valenciennea 



86. Lower jaw with one or two pairs of canine teeth behind symphysis ; 

 scales cycloid, 110 to 170 in longitudinal series ; branched rays of 

 dorsal and anal fins 19 to 32 Ptereleotris 



Genus HERREOLUS H. M. Smith 



Hirrrolu.s H. M. Smith. Journ. Siam Soc, Nat. Hist. Suppl., vol. 8, p. 190, 1931. 

 (Type, Heirea ■formosa H. M. Smith.) 



The name Eerreolus (Smith, 1931d, September), was proposed for 

 Herrea (Smith, 1931a, March), which had been preoccupied by Whit- 

 ley in 1930. Another substitute for Herrea., namely, Ilerreich thys^ was 

 proposed by Koumans (1931), but that designation is an undoubted 

 synonym of Herreolus. Koumans' paper bears no date of publication 

 but the title page indicates that proof sheets were offered to the faculty 

 of science and natural history of the University of Leiden December 4, 

 1931, which would be the earliest possible date assignable to the 

 publication. 



The original description of this genus was defective and incorrect in 

 a number of important elements. For instance, the definition left 

 doubtful the actual family, whether Gobiidae or Eleotridae, to which 

 the fish belongs. For this reason it is deemed desirable to offer a new 

 generic description and to indicate relationships. 



The genus 'Herreolus is an eleotrid, having the ventral fins entirely 

 separate. The body is very elongate, and both body and head are 

 strongly compressed. The head is of moderate size, blunt, with large 

 eye, wide and flat interorbital, short snout, and very oblique mouth, 

 with maxillary extending to a point under anterior margin of eye. The 

 teeth are small and pluriserial, those in the outer row of the lower jaw 

 enlarged but not caninoid. The gill openings are restricted to the sides 



