3138 Bulletin United States National Museum. 
Page 132. After Tachysiirun melanopus (Giinther), insert the following: 
200 (a). TACHYSrurs FKST.K (Boulenger). 
Head 4; depth 4; eye 64, above level of mouth, in anterior part of head. 
14. 17; A. 23. Premaxillary band of teeth 4 times longer than broad, i;s 
•width 2^ in eye, or equal to width of groups of vomer and palatine 
teeth, these last granular, forming 2 large, oblique grou]>s, separated on 
the median line by a s])ace equal to ^ diameter of eye; width of head 
in its length ; occiput and occipital prolongation granular, the last as 
long as wide, and with blunt spine; fontanelle narrow, commencing in a 
groove between the anterior nostrils and reaching occiput, not reaching 
occipital prolongation ; barbels flattened ; maxillary as long as head, reach- 
ing beyond base of pectoral spine; external mandible a little shorter, 
as long as the internal; gill-membrane with a free border broken at the 
isthmus; anal spine striated, IJ in head, its anterior edge feebly toothed 
except at extremity, which has, like the posterior edge, stronger and 
more retrorse teeth ; adipose dorsal twice as far from rayed dorsal as from 
caudal, its base 14 in base of rayed dorsal; pectoral spine 14 in head, its 
external edge furnished with a series of soft, small tubercles on its basal 
half, anterior edge armed with 'feeble retrorse teeth; ventral shorter, 
reaching origin of anal ; caudal deeply forked; caudal peduncle twice a.s 
long as deep; axillary jiore present, much smaller than the nostril. Color 
steel blue above, silvery below. This species closely resembles Tachyaiiriis 
Jirojius, Bristol. Length 210 mm. One siiecimen known, from Narrangal, 
Ecuador. (Boulenger.) (Xamed for the collector of the tyjie. Dr. Eurico 
Festa.) 
Arius /estce, Boulenger. Bollettino del Mas. di Zool. ed. Anat. Comp, della I’niv. di 
Toi'iiio, Vol. XIII. o. 3‘29, 5, Dec. 2, 1898, Narrangal, Ecuador. 
Page 135. After Ictahuua meridionaUs (Giinther), insert: 
76(a). ISTLARIUS, Jordan A: Snyder. 
Jstlarinn, .Toruan A Snyder, Bull. U. S. Fish Com. 1899 (1900), 118 (baUanua). 
Body rather deep and comiiressed; head not widened, nor greatly 
depressed; eye large; lower jaw included; teeth in villiform bauds on 
premaxillaries and dentaries; the premaxillary band convex anteriorly, 
with a short angular posterior extension on each side, no division of 
the baud at synqihysis; dentary band broad anteriorly, growing narrow 
and pointed posteriorly, with a distinct median division; no teeth on 
vomer or palatines; villiform teeth on upper and lower jiharyngeals ; 
gill-rakers on first arch 17, long and slender; branchiostegals 8; air 
bladder very large, extending almost to posterior end of body cavity, 
divided by a transverse constriction into two parts of nearly eijual 
length, the anterior heart-shaped, posterior jiart oval; snpraoccipital 
bone widely separated from iuterspinal; humeral process short, almost 
hidden by tlie skin; lateral line extending from below insertion of 
dorsal to caudal; skin covered with minute, hairlike villi; skin of 
bead comjiletely concealing bones of skull; barbels 8. Spines with 
