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PROCEEDINGS OF THE NATIONAL MUSEUM 



(1957), in an aquarium publication, has recorded and published pho- 

 tographs of two forms of Nannostomus , one of which is stated to be 

 anomalus, the other aripirangensis; both of these photographs appear 

 to be of beckfordi, showing two of its several geographical color vari- 

 ants. Neither has a color pattern exactly like that described for the 

 original aripirangensis. 



Until thorough collections of Nannostomus can be made on the 

 Island of Aripiranga, the problem of the distinctness of arijnrangensis 

 cannot be settled; however, I tentatively prefer to consider aripiran- 

 gensis one of the several geographically distinct populations of 

 beckfordi. 



Figure 4. — Anal fin of male Nannostomus beckfordi, SL 31.0 mm., SU 50261. 



Nannostomus beckfordi appears to be a polytypic species with a 

 wide geographical range, known from the Guianas and for a con- 

 siderable distance (about 700 or more air miles) up the Amazon 

 River. Adequate collections and studies will undoubtedly show that 

 this species consists of several distinct populations, some of which 

 may prove to be subspecies. Studies of color variation, variation in 

 certain body proportions (especially head depth compared to body 

 length and caudal peduncle length), vertebral counts, and arrange- 

 ment of tooth cusps will probably be of great value in studying sub- 

 specific population differences. 



Specimens examined.— Three, SU 50256, SL 22.0-22.7 mm., Brazil, State of 

 Pard, Belem, May 18, 1924, Carl Ternetz.— Four, SU 50262, SL 22.5-27.5 mm., 

 Brazil, State of Pard, brook into Tdpajos near Santardm, Aug. 2, 1924, Carl 

 Ternetz.— Forty-four, SU 50257, SL 16.0-29.0 mm., Brazil, State of Pard, south 



