PHARYNGEAL TEETH OF FISHES. 207 
Levciscus poputa. The Dace. Fig. III. 
Has five short, thin, horny gill-rakers on the cerato-hypo 
of the first branchial arch, with two on its epibranchial. The 
longest one near the angle is half the depth of the gill lamina 
below it. The other arches are furnished with but compara- 
tively few gill-rakers set at a distance apart. The pharyngeal 
teeth are slightly hooked at the extremity, and are set in a 
double row, 5-2 and 2-5. They bite against a callous pad. 
LEUCIScUS | : 
BRYTHR OP. 
»THALSI UG. 

Fic. III. 
Tinca vutearis. The Tench. Fig. III. 
Has nine short, horny gill-rakers, the longest a little less 
than half the depth of the gill lamina below it; they diminish 
in size as they get away from the angle—these are on the first 
cerato-hypobranchial arch. There are three on the epibranchial. 
There are similar gill-rakers on the other arches, and the whole 
forms a very efficient filter apparatus. The pharyngeal teeth 
are in a single row of wedge-shaped teeth, with a slight hook at 
their ends. The upper back part of the gullet has a thick 
mucous lining, and a callous pad for the teeth to bite against. 
Four loose extra teeth were obtained in the specimen examined. 
and figured. 
