PHARYNGEAL TEETH OF FISHES. 205 
marked corrugations that fit inte the depressions caused by the 
upstanding gill-rakers. 
Lasgo Row1ta. The “Rohu” of the Indian bazaars. Fig. IL., 3. 
The thin, horny, short gill-rakers are very numerous, set 
closely together, and covered with a mucous secretion that 
obliterates them individually, and that gives to the gill-arches 
the appearance of having a fringed band on each side. The 
pharyngeal teeth (see illustration) are in three series, plough- 
shaped, and work against a projection of the basi-occipital that 
is covered with a thick, hard skin, which is striated. The 
arrangement of the teeth is such that they present a flat surface. 
The worn surface of the functioning teeth shows well in the 
illustration; two of them were found to be loose. Six extra 
teeth were found embedded in the tissues surrounding the 
working teeth. The lower pharyngeal bones have holes through 
them, and no diaphragms as in the Carp. 
Lapio nitoticus. A Nile fish. 
Has thirty-two straight, very fine, horny gill-rakers on the 
first cerato-hypobranchial arch, with twelve on the epibranchial. 
The inner and outer surfaces of the other gill-arches are set 
with similar gill-rakers that interfold, forming a complete filter. 
The pharyngeal teeth are conically pointed. 
Barsus BynNu. A Nile fish. 
Has fourteen horny, slightly curved gill-rakers on the first 
cerato-hypobranchial arch, with three on the epibranchial. The 
other arches covered with soft gill-rakers that fit closely together 
and make a complete filter. No callous pad was observed, the 
teeth working against the lining membrane-of the back of the 
gullet. 
Barsus vunearis. The Barbel. Fig. III. 
There are seven short, stout, horny gill-rakers on the first 
cerato-hypobranchial arch, with three on its epibranchial. The 
longest one, at the angle, is one-third the depth of the gill 
lamina below it. The gill-rakers on the other arches are much 
more numerous, and the general appearance is like that of a 
Carp’s gullet (see ante), but each one is covered with papille, 
