72 MEMOIRS OF THE CARNEGIE MUSEUM. 



Eigenmann, Reports Princeton Univ. Exped. Patagonia, Vol. Ill, 1910, p. 429. 



Range: Maldonado to Rio Grande do Sul. 



The types of interruptus came from Maldonado and the specimens collected 

 by Carey at the same place (No. 20698, M. C. Z.) are more than probably inter- 

 niptus. These specimens are specifically distinct from the Paraguayan specimens, 

 heretofore referred to C. interruptus. A careful comparison with the excellent 

 fresh specimens from the Paraguay river and others from various places in the 

 San Francisco basin, collected by Haseman, shows that they are so similar, that 

 the Paraguayan form hitherto referred to interruptus must be referred to C. piaba. 



Fig. 24. Interhsemals in Cheirodon interruplm Jenyns. 6818, C. M. 



Specimens from Rio Grande do Sul, the type locality of C. monodon, are very 



similar to C. interruptus, and monodon may be considered a variety of interruptus. 



6815a-k, C. M., two males, eleven females, largest 45 mm. Rio Guahyba, 



Porto Alegre, Rio Grande do Sul. Jan. 21, 1909. Haseman. 

 6817a-d, C. M., fourteen, largest 40 mm. Santa Maria, Rio Vaccacahy- 



Mirim, secondary tributary of the Rio Jacuhy, Rio Grande do Sul. Hase- 

 man. 

 6818a-x, C. M., three males, largest 43 mm., twenty-.six females, largest 49 mm. 



Cachoeira, Rio Jacuhy, Rio Grande do Sul. Jan. 26, 1909. Haseman. 

 6852a, C. M., one female, 47 mm. Cacequy. Haseman. 

 846 & 847, M. C. Z., twelve, poor, largest a male about 35 mm. long. Uruguay 



river. Wyman. 

 20698, M. C. Z., forty, largest about 60 mm. and 20699, M. C. Z., one, 46 mm. 



Maldonado. T. G. Carey. 

 6816a-j, C. M., one male, 42 mm., nine females, largest 52 mm. Cacequy, Rio 



Ibicuhy, into Rio Uruguay. Jan. 31 & Feb. 1, 1909. Haseman. 

 This species can readily be distinguished by the naked area behind the third 

 suborbital and by the numerous interhaemals. They extend from the anal to the 



