526 MB. G. A.. BOtJLBNGEE ON FISHES [Juue 18, 



A single specimen from Paraguay. 



This species appears to be nearest allied to P. francisci, LUtk., 

 which is only known to me from the description. 



7. Ch.^tostojius gigas, sp. n. 



15 upper and 19 lower teeth on each side. Depth of body 4^ 

 times in total length, length of head 2^ times. Head a little 

 longer than broad, entirely rough with small spines ; snout broadly 

 rounded ; diameter of eye 1 1 times in length of head, 4| times in 

 interorbital width, 6 times in length of snout ; anterior border of 

 orbit with enlarged spinules ; no postorbital groove ; erectile 

 prseopercular spines very strong, the longest 2| diameter of orbit ; 

 barbel a little longer than diameter of orbit. Throat and belly 

 studded with small rough shields. Dorsal I 10 ; all the rays rough 

 with spinules, the first measuring | length of head. Pectoral spine 

 as long as head, covered with small spines, the longest of which 

 are hooked and nearly equal diameter of orbit. Ventral I 5, 

 as long as first dorsal ray. Anal I 5. Caudal obliquely truncate, 

 lower ray longest. Shields on body rough with ridges of strong 

 spinules, 25 in a longitudinal series. Brown, densely covered all 

 over with round black spots. 



Total length 530 millim. 



A single specimen from Paraguay. 



This fish, the largest known of the genus, is possibly the adult 

 of G. acuhatus, Perugia, in which, however, the ventral region is 

 entirely naked. 



8. HXPOPTOPOMA. GUEISTTHERI, sp. n. 



Head not narrowed behind the eyes, its width equal to length 

 of posterior border of orbit, its length 2| to 3 times in total ; 

 diameter of orbit 5 to 5^ times in length of head, 2| to 2^ times 

 in length of snout, 3 to 3g times in interorbital width ; barbel 

 very small ; head-shields as in H. ilioracatum. Dorsal I 6, first 

 ray as long as head to upper angle of gill-cleft. Pectoral as long 

 as first dorsal ray, extending as far as ventrals, not reaching 

 anal. Caudal deeply notched, middle rays half as long as outer. 

 Two pairs of large, transverse pectoral shields, pi'eceded by a 

 transverse series of four small shields, the outer of which are in 

 contact with the suborbital shields ; three or four large ventral 

 shields on each side, the anterior of which are usually separated 

 by an azygos shield. Shields on body spinulose but not keeled, 

 20 to 22 on each side ; 3 shields between the occipital and the 

 dorsal, 12 between the dorsal and the caudal. Olive ; dorsal and 

 caudal fins with black spots, which may form two curved bands 

 on the lower lobe of the caudal. 



Total length 65 milHm. 



Numerous specimens from Descalvados, Matto Q-rosso. 



The fish described and figured by vSteindachner as H. thoracatum, 

 Gthr., belongs to a distinct species, for which I propose the name 

 H. steindachiicri. His H. bUobatum is distinct from Cope's, which 



