THE CATFISHES OF VENEZUEtLA — SCHULTZ 247 



Genus HOPLOMYZON Myers 



Hoplomyzon Myers, Stanford Ichth. Bull., vol. 2, No. 4, p. 94, 1942. (Type, 

 Hoplomyzon atrizona Myers.) 



It was with more than usual interest that I examined, late in 1942, 

 the description of the new genus Hoplomyzon, especially after I had 

 described two new genera in my manuscript in preparation on the 

 Venezuelan catfishes. One of these, Dupouichthys, I still believe is 

 valid, but the other one, after careful study, I consider to be the 

 same as Hoplomyzon, but that could not be determined from the 

 description. Since my two specimens from the Rio Motatan of the 

 Maracaibo Basin resembled H. atrizona in so many details, I sus- 

 pected at once that Dr. Myers m his necessary haste to prepare the 

 paper for publication may have overlooked the barbel at each corner 

 of the mouth. The artist who drew one of the paratypes did not 

 include that pair of barbels either. 



At my request, Miss Margaret Storey, in the absence of Dr. Myers 

 in Brazil, kindly lent a paratype, Stanford University No. 36495, of 

 Hoplomyzon atrizona, and, upon examination, the barbels were seen 

 to be as obvious as those on my specimens from the Rio Motatan, 

 Maracaibo Basin. This paratype, however, differed slightly in color 

 from my specimens, so again I wrote to Miss Storey to see if the type 

 could be examined. She asked William Gosline to examine the type, 

 and he replied to me as follows: 



"I have reexammed the type of 'the species that Myers described 

 as Hoplomyzon atrizona,' and am enclosing a rough sketch of the 

 mouth parts. The only additional barbel I can find is at the point 

 indicated." 



His sketch of H. atrizona confirmed my suspicion that a barbel at 

 the front corners of the mouth should have been drawn and described, 

 as the pair was present, as shown in figure 4, a. 



The generic description follows: Head depressed, under surface of 

 the body forming a plane surface, body quadrangularly shaped an- 

 teriorly and hexagonally shaped in cross section posteriorly; greatest 

 depth at origin of dorsal fin, greatest width at pectoral fin insertion; 

 body armed by a dorsal series of paired bony plates beginning near 

 origin of dorsal fin and a similar series of paired plates along the ven- 

 tral side beginning behind anus; along the lateral line at each pore is a 

 tiny platelet; behind the anal and dorsal fins the plates are close to- 

 gether and probably fused; all plates are covered with a thin skin; 

 skin everywhere rugose, especially on the head; vent equidistant be- 

 tween rear edge of basal membrane of anal fin and tip of snout; a 

 vertical line through hisertion of pelvics about equidistant between 

 such a line through insertion of pectorr Is and origin of dorsal fin; anal 

 origin under base of next to last ray of dorsal; anus about twice the 



