G48 General Notes. 
the air-bladder of Ageneiosus has a bony base, the membranaceous 
portion being restricted toa membrane stretched across the opening 
of the bony capsule ; the whole air-bladder is likewise surround 
above and behind by the lateral processes of the modified vertebra 
and anteriorly partly by the scapula, but the coalesced vertebre are 
much longer than in Hypophthalmus, and the lateral processes 
and scapular process are widely separate below. 
Many changes in the classification of the Nematognathi have 
been found necessary. The Bunocephalids (= Aspredinidz) usually 
associated with the Loricariide have no skeietal affinities with that 
family, being much more nearly related to the Siluridæ. The 
genus Cetopsis, as before stated, is more closely related to the species 
of Pygidiidee (—Trichomycteridze) than to the species of Doradine, 
with which it has usually been associated. The genera Heptapterus 
and Nannoglaris, on the contrary, are closely related to some of the 
species of Giinther’s Pimelodus, and have no real affinity with the 
Pygidiide. 
(6) Opercle none ; adipose fin none ; neural spines of the coalesced 
vertebre forming a ridge from the occipital to the dorsal fin. 
Caudal vertebre greatly compressed; their neural spines expanded, 
a o aee eee... Bunocephalide. 
(bb) Opercle well developed and movable ; adipose fin normally 
present ; occipital process sometimes forming a bony bridge mon 
occipital to the dorsal plate. Caudal vertebræ normal ; the neura 
GRICE BPO DED a aeaa erens aaa Caaet Urlag. 
(aa) Air-bladder rudimentary ; one on either side of the coalesced 
vertebræ, and entirely surrounded by a bony capsule. 
