506 PROCEEDINGS OF THE ACADEMY OF [J^ty, 



(jg. Olive, the 9 or 10 anterior scutes with vertical series"of l^lackish 

 spots; base of the dorsal fin equal to the space between the 

 dorsal and adipose fins ; depth 3^ in the total length ; eye al)out 

 3 in the head; spines of the fins very strong and long, dorsal 

 spine as high as the body, pectoral spine shorter; 4-5 azygos 



shields (Giinther), armatus. 



cc. Caudal fin with 4-5 dark vertical bars; dorsal with dark markings, 



/z. Dorsal fin with 2 irregular crossbars; sides of body with series of 



dark blotches ; middle of the lower fins blackish, . . paleatus. 



hh. A dark vertical bar on the first dorsal rays, sometimes extending 



on to the body below ; anal fin barred or spotted ; ventrals and 



pectorals plain, punctatus. 



hhh. Dorsal fin with 5 longitudinal rows of dark spots; 6 narrow bars 

 on caudal. Top of head tinged with brown; a yellowish band 

 across snout, otherwise the fish without color, . aurofrenatus. 

 hhhh. Dorsal with black spot on ends of rays. 



i. Anal spotted; dark brown above, 3 series of dark spots along 



middle of side, trilineatxis . 



a. Anal plain. 



j. Lat. plates |f ; azygos plates none; a pale band on side; clavicle 

 and opercle with blue reflections (Cope), .... acutus. 

 jj. Lat. plates f^; azygos plates 4; numerous dark dots on the side 

 shields which are wanting on middle line of side; a black spot 

 at the base of the dorsal spine (Cope), .... amphihdus. 

 ccc. A hastate black spot at base of caudal fin, margined behind by 

 white; a black lateral band, hastatus. 



34. Corydoras microps sp. nov. 



Type No. 9,892, one specimen (No. 100). From a small lagoon, half 

 dry, near the Rio Branco (Matto Grosso, Brazil), where there were 

 thousands of these fishes. Co-types No. 9,893, three specimens (260). 

 From Arcgua, in a brook which empties into the Laguna Ypacara. 

 Sides metallic green. June, 1901. Co-types No. 9,894, one specimen 

 (No. 236). Aguadas, near the Arroyo Trementina. December, 1900. 

 Co-types No. 9,895, two specimens (No. 215). H cm. From Arroyo 

 Pypucii. January, 1901. 



Short, deep, ventral outline almost straight to base of anal. Pro- 

 file steep to nostrils, less steep and evenly rounded from nares to 

 dorsal. 



Eye 2-2^ in snout, 4^-5 in head, 2^-2^ in interorbital. 



Mouth inferior, snout conical; maxillary barbels scarcely reaching 

 gill-openings, labial barbels slightly longer. Fontanel elongate, nar- 

 row, extending into the base of the occipital. 



Coracoid processes narrow. The distance between them equals ^ 

 distance between bases of pectoral spines. 



Three to four azygos plates before the adipose fin. 



