THE AMERICAN TETRAGONOPTERINAE. 



83 



Collector 

 Haseman 

 Haseman 

 Haseman 



This species differs from the Amazonian M. oligolepis in having usually 

 but twenty-five scales in the lateral line instead of thirty or thirty-one. 



In many of the smaller specimens the lateral line is either interrupted, i. e. 

 it skips a scale or more, or it is incomplete. The incompleteness is positively 

 correlated with the shorter lateral line. This is especially well brought out in 

 the specimens from San Luiz de Caceres. These specimens with a complete 

 lateral line have usually thirty scales in the lateral line, while those with an 

 incomplete lateral line have usually only twenty-five though of the former 

 one has but twenty-five and of the latter one has as many as twenty-eight scales 

 in the lateral line. Out of eighty-four specimens examined twenty-nine have 

 imperfect lateral lines. 



The count of the anal rays and lateral lines is given in detail for differ- 

 ent localities in the first part of the following table, and summarized in the 

 second part of the table for those specimens of both M. oligolepis and sanctae 

 filomenae in which the character of the entire line could be determined. 



Correlation between completeness of the lateral line and anal and number of scales in the lateral line. 



Lateral line complete 

 Lateral interrupted 

 Lateral line incomplete 



