254 The South American Cat-fishes 



g. Scutes of body without keels. Head, much depressed, 

 a little longer than broad. Occipital and nuchal regions 

 flat. Snout broad, granulated except at tip. Diameter 

 of eye equals ^ of the interorbital. .schomburgki Giinth. 



ff. Pectorals extend to middle of ventrals almost. 



h. Scutes of body with prominent serrated keels. Head 

 large, broader than long, 3i in total. Orbit elevated. 

 Interorbital i-ather concave. Eye large, its diameter 

 equals distance to posterior edge of the head and more 

 than ^ of interorbital. Base of dorsal equals its distance 

 from caudal. Pectoral ray covered behind with seti- 

 form spines medians (Kner) . 



hh. Scutes of body without keels. Head large, little 

 longer than broad. Base of dorsal very long, equals 

 nearly twice the distance from the caudal to the dorsal. 

 First ray of pectoral covered with small hooked spines 

 toward the tip. Eye 2} in interorbital, 5| in head. 

 Dorsal and caudal fins and body covered with small 

 white spots longipinnis sp. nov. 



ee. Caudal not truncated, lobes of equal length. 



i. Lower lobe of caudal strongest. Body covered with round 

 black spots. Head not depressed, broad as long, length in 

 total 3:^. Interoperculum with about 16 setiform spines, 

 longest 3 in the head. Pectoral reaches nearly to middle 

 of ventral. Eye 2 in interorbital. L. 1. 26. 



obligospilus (Giinth). 



ii. Upper and lower caudal lobes of equal strength. Body 

 without spots. Head short and high. Width at opercles 

 one ocular diameter less than greatest length. Pre- 

 opercle with numerous slender spines. Orbital diameter 

 as long as barbel, 2^ to 3| in snout, 5 to 6^ in head, 2 to 2^ 

 in interorbital vittatus (Steind). 



aaa. Anal rays six. 

 j. Dorsals 1-7. 



k. Lateral scutes keeled, caudal obliquely truncated. 



I. Eye 3 in interorbital ; head with prominence on occiput. Keels 

 on lateral scutes serrated. Head much depressed, length 

 equals | of total. Keels on lateral scutes serrated. Lower lobe 

 of caudal ^ longer than uiijier. Interopercle with 15-18 seti- 

 form spines. L. 1. 25-26 scaphirhynchus (Kner). 



II. Eye 1^ in interorbital. Head without prominence. 



m. Dorsal a little longer than high. Snout granulated except 

 at tip. Upper surface of head and body with rather irreg- 

 ular yellowish spots pictus (Kner). 



