LIST OF PLATES. 



Xlll 



XXXVI-XXXIX. 



XL. 



Pimelodella hasemani Eigenmann. 



Pimelodella laticeps Eigenmann. 



Pimelodella notomelas Eigenmann. 



Pimelodella metce Eigenmann. 



Piynelodella holiviana Eigenmann. 



Pimelodella itapicuruensis Eigenmann. 



Pimelodella meeki Eigenmann. 



Pimelodella meeki. 



Pimelodella griffini Eigenmann. 



Pimelodella mucosa Eigenmann. 



Pimelodella grisea Eigenmann. 



Pimelodella chagresi (Steindachner). 



Pimelodella euicenia Regan. 



Typhlobagrus kronei Ribeiro. 



Pectoral spines of species of Pimelodella viewed from 



above and greatly magnified. 

 Maps showing the geographical distribution of the 



PygidiidcE. 

 Anatomical details of the structure, principally of the 



heads, of Eremophilus mutisii Humboldt and 



Henonemus punctatus Boulenger. 

 Eremophilus mutisii Humboldt. 

 Paracetopsis occidentalis (Steindachner). 

 Nematogenys inermis (Guichenet) . 

 Hatcher ia maculata (Cuvier & Valenciennes). 

 Tridens melanops Eigenmann & Eigenmann. 

 Branchioica bertonii Eigenmann. 

 Scleronema, Hatcheria, Pygidium, and Pseudostego- 



philus. 

 Pygidium. 

 Pygidium. 

 Pygidium,. 

 Pygidium. 

 Pygidium. 

 Pygidium. 

 Pygidium. 

 Pygidium . 

 Vandellia. 



Eremophilus mutisii Humboldt. 

 Eremophilus mutisii Humboldt, juv. 



