256 MEMOIRS OF THE CARNEGIE MUSEUM 



"Essa predominancia hereditaria, tao frisante aqui, e certanaente um docu- 

 mento de valor para a theoria genealogica, quando se ve que em 35 outros ex- 

 emplares de todos os tamanhos, apenas uma estricta fenda indica a posigao que 

 outr'ora occupou esse importantissimo orgao. No exemplar que nos dissecamos. 

 nao conseguimos encontrar, siquer, vestigios do nervo optico e o seu logar estava, 

 ao contrario, occupado pelo grosso ramo nervoso do barbilhao maxillar." 



It seems evident from the fact that the skin and the bones near the eye have 

 undergone little or no change, while the eye has vanished but occasionally de- 

 velops, that the process of its degeneration was very rapid. 



EXPLANATION OF PLATES. 



Plate XXIX. 



Fig. 1. Pimelodella serrata Kigenmarm. Type, C. M. No. 6967, 67 mm. San Joaquin, 



Bolivia. 

 Fig. 2. Pimelodella cristata (Miiller & Troschel). I. U. M. No. 12064, 176 mm. Below 



Potato Landing. 

 Fig. 3. Pimelodella avanhandavce Eigenmann. Type, C. M. No. 6969, 85 mm. Salto 



Avanhandava. 



Plate XXX. 

 Fig. 1. Pimelodella hasemani Eigenmann. Type, C. M. No. 6968, 81 mm. San 



Antonio de Madeira. 

 Fig. 2. Pimelodella laticeps Eigenmann. Type, C. M. No. 6957, 62 mm. Sapucay, 



Paraguay. 

 Fig. 3. Pimelodella notomelas Eigenmann. Type, C. M. No. 6955, 51 mm. Caceres, 



Plate XXXI. 

 Fig. 1. Pimelodella metce Eigenmann. Type, C. M. No. 7141, 77 mm. Rio Negro. 



Villavicencio. 

 Fig. 2. Pimelodella boliviana Eigenmann. Type, C. M. No. 6964, 90 mm. Santa 



Cruz de la Sierra. 

 Fig. 3. Pimelodella itapicuruensis Eigenmann. Type, C. M. No. 6974. Rio Itapicuru. 



Plate XXXII. 

 Fig. 1. Pimelodella meeki Eigenmann. Type, Field M. No. 3400. Sao Paulo. 

 Fig. 2. Pimelodella meeki Eigenmann. C. M. No. 6980, 117 mm. Sao Paulo. 

 Fig. 3. Pimelodella griffini Eigenmann. Type, C. M. No. 6962, 87 mm. Sapucay, 

 Paraguay. 



