218 PROCEEDINGS OF THE NATIONAL MUSEUM ?ou 94 



Color. — Grayish to light brownish above, white below, the color 

 abruptly paler about an eye diameter above the blackish lateral line; 

 two embedded black spots near base of each lobe of the caudal fin; 

 black spots, more or less embedded, between bases of each ray of 

 dorsal fin; lower lobe of caudal fm darker, the ventral margin distinctly 

 pale and contrasting with the blackish pigment; under the eye a dark 

 band, with the cheek below abruptly white; peritoneum white. 



Remarks. — This new subspecies differs from other forms referred to 

 the genus Megalonema as indicated in the key on page 215. The most 

 distinct difference is in the color along its side, the pale area extending 

 «,bove the lateral line, while in platycephalum the darker pigment is 

 continuous to below the lateral line. 



Named psammium in reference to its occurrence over sandy areas 

 of rivers. 



Genus CETOPSORHAMDIA Eigenmann and Fisher 



Cetopsorhamdia Eigenmann and Fisher, in Eigenmann, Ann. Carnegie Mua., vol. 

 10, p. 83, 1916. (Type, Cetopsorhamdia nasus Eigenmann and Fisher.) 



Eigenmann described the genus Chasmocranus (genotype: C. longior 

 Eigenmann) and referred another species, C. brevier, to it. An exam- 

 ination of a paratype, U.S.N.M. No. 66133, indicates that Chas- 

 mocranus has a depressed head and backward-projecting angles at the 

 outer ends of the prem axillary band of teeth, as described by Eigen- 

 mann. Gosline (Stanford Ichth. Bull., vol. 2, No. 3, p. 88, 1941) 

 recognizes the genus and refers to it the following species: C. 

 truncatorostris Borodin, 1927, and C. quadrizonatus Pearson, 1937. 

 Perhaps these species, along with those referred to the genera Impar- 

 finis and Pariolius by Gosline {loc. cit.), need careful reexamination, as 

 certain of these species do not have their heads depressed so much as is 

 indicated in Gosline's key in contrast to the "head conical" for 

 Cetopsorhamdia. 



The forms described as new below have the outer ends of the pre- 

 maxillary band of teeth rounded. 



KEY TO THE SPECIES OF CETOPSORHAMDIA 



la. Total length of adipose fin contained in standard length less than 4 times, and 

 head in standard length about 4.6 to 4.8 times. 

 2a. Total length of adipose fin 0.7 times in distance from dorsal origin to adipose 

 origin and 2.9 in standard length; no pale bars on back or sides, color 

 plain darkish; distance from pelvic insertion to anal origin 2.1 in snout to 

 pelvic insertion; length of shortest midcaudal fin rays in total length of 

 adipose fin 3.1, in longest caudal fin ray 2.2, and 2.5 in distance from 

 dorsal origin to adipose origin (Magdalena Basin near Honda). 



Cetopsorhamdia boquillae Eigenmann * 



' Cetopsorhamdia boquillae Eigenmann, Mem. Carnegie Mus., vol. 10, No. 1, p. 37, pi. 1, flg. 3, 1922 

 (Boquilla). 



