244 Fre~tp Museum or Natura History — Zoétroey, Vor. X. 
Body rather robust; profile from snout to dorsal straight and gently 
elevated in female, concave in adult males; head depressed, its width 
1 to 1.8 in its length; posterior part of body rather strongly compressed; 
snout short, broad; about equal to diameter of eye; eye 4.4 to 6.65 in 
head; interorbital 1.53 to 1.63; mouth broad; a pair of maxillary barbels, 
with a bone extending to anterior margin of eye in female, almost or 
quite to gill-opening in male; chin with 2 pairs of barbels; teeth in the 
jaws in bands; gill-opening small; dorsal plate rather broad; humeral 
process narrow, pointed slightly upward; dorsal spine in female some- 
what shorter than head, notably longer than head in the male, with 
barbels on its anterior margin, at least in young and in males; origin of 
dorsal more than half as far from tip of snout as from tip of adipose; 
adipose fin over posterior part of anal; caudal fin forked, both lobes 
pointed, equal to or longer than head; anal fin rather low, with heavy 
membrane on its base, length of its base shorter than width of head; 
ventral fins reaching origin of anal; dorsal fin not nearly reaching base 
of ventrals, the spine usually about equal to length of head. 
Color dark above, pale below; sides variously spotted or marked with 
black. Usually with a dark spot or elongate blotch on middle of side 
below dorsal; some specimens with roundish black spots on sides of head 
and caudal peduncle. Fins unmarked. Our largest specimen much 
darker than the others. 
There are 8 specimens in the present collection, ranging in length 
from 87 to192 mm. All are from the lower Rio Tuyra. One specimen 
is from several miles above and the others from several miles below the 
head of the tide. 
This species is very closely related to T. fisheri Eigenmann, from 
which it differs mainly in the shape of the caudal, which has a much 
more concave margin, and longer and more pointed lobes.. It also 
differs from the latter in the more posterior position of the dorsal and 
in the shorter anal. 
Habitat: Rio Tuyra Basin. 
5. Genus Ageneiosus Lacépéde. 
Ageneiosus Lacépéde, Hist. Nat. Poiss., V, 1805, 132 (type Agenetosus 
armatus Lacépéde). 
Pseudageneiosus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 108 (type 
Ageneiosus brevifilis Cuvier & Valenciennes). 
Body elongate; snout much longer than eye, with maxillary barbels 
only; eyes lateral; the orbit without a free margin; occipital process 
