32 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 119 



Guiana, Gluck Island, Essequibo River, 1908, Carl H. Eigenmann. — One (para- 

 type of P. erythnirus), CAS(IUM) 11695, SL 25.5 mm., British Guiana, Rupununi 

 River, Twoca Pan, 1908, Carl H. Eigenmann.— One, CNHM 50162, SL 27.0 mm., 

 British Guiana, Rockstone, Essequibo River, Mar. 1937, E. R. Blake. — Five, 

 SU 50223 (one alizarin preparation), SL 25.0-30.0 mm., British Guiana, no other 

 data. — Two, SU 18472 (one alizarin preparation), SL 31.5-32.0 mm., aquarium 

 specimens said to be from "the Amazon," sent to Dr. G. S. Myers by Frederick 

 Stoye, no other data. — Seven, SU 50220, SL 29.5-32.5 mm., aquarium specimens 

 probably from British Guiana, 1955.— Two, SU 50434, SL 21.0-22.1 mm., British 

 Guiana, Moreby Creek, Rupununi River near Karanambo, Essequibo drainage, 

 Sept. 17, 1957, Rosemary Lowe (McConnell).— Two, SU 50437, SL 23.2-24.8 mm., 

 British Guiana, Karanambo, "Grass Pond," Rupununi River, Essequibo drainage, 

 Sept. 14, 1957, Rosemary Lowe (McConncU).— Two, SU 50432, SL 24.0-26.0 

 mm., British Guiana, "Crane Pond Creek," Karanambo Rupununi River, Esse- 

 quibo drainage, Sept. 14, 1957, Rosemary Lowe (McConnell). — Two, SU 50440, 

 SL 19.0-27.0 mm., British Guiana, Rupununi District, Nappi River and other 

 Tocatu drainage creeks, Rio Branco drainage, Sept. 20, 1957, Rosemary Lowe 

 (McConnell). 



Nannostomus marginatus Eigenmann 



Figure 8 



ICyprinodon amazona Eigenmann, 1894, p. 627 (in part; original description; type 

 locality: Lower Amazonas; types apparently lost). — Garman, 1895, p. 28 

 (in part; copied description). — Hubbs, 1926, p. 16 (in part; discussion of 

 identity). — Fowler, 1954, p. 216 (in part; listed). 



Nannostomus marginatus Eigenmann, 1909, p. 41 (original description; type 

 locality: British Guiana, Maduni Creek, Mahaica River; holotype in Chicago 

 Natural History Museum) .—Eigenmann, 1910, p. 427 (listed); 1912, p. 281, 

 pi. 37, fig. 4 (description). — Innes, 1935, p. 154 (description from life and 

 photograph; see also later editions). — Hoedeman, 1950, p. 20 (description; 

 figures).— Boeseman, 1952, p. 184 (Surinam); 1953, p. 16 (Surinam); 1954, 

 p. 18 (Surinam). — Axelrod and Schultz, 1955, p. 241 (description and 

 aquarium notes). — Sterba and Tucker, 1963, p. 211 (description and aquarium 

 notes) . 



ICyprinodon amazonus Eigenmann, 1910, p. 456 (in part; listed). 



Nannostomus marginatus piduratus Hoedeman, 1954a, p. 87 (original description; 

 type locality: "A ditch near Zonderij II, Surinam"; types in Amsterdam 

 Museum) . 



Diagnosis. — This species is the deepest bodied of all nannosto- 

 minans ; only egg-filled females of Nannostomus beckfordi were found to 

 have a body depth as great as the most slender specimens of marginatus. 

 The body depth of marginatus is 3.5 to 4.0. Their caudal peduncle is 

 the deepest of all nannostominans, 7.5 to 8.5 in standard length. In 

 addition, marginatus may be distinguished from all other nannosto- 

 minans by the following combination of characters: Primary, second- 

 ary, and tertiary horizontal stripes all present; maxillary tooth rarely 

 present; 21 to 23 scales in a lateral series; 7 + 12 giU rakers; 31 to 33 

 vertebrae; male anal fin with unmodified fin rays. 



Description. — Body elongate, robust; sides flattened and body 



