PHARYNGEAL TEETH OF FISHES. 421 



general scheme in the anatomy of a fish's gullet. It is subject 

 to modifications in different cases, which will be noticed, if 

 important, when treating of different fishes where such occur. 



The branchial arches on their concave surface carry the gill- 

 rakers, horny protuberances, often like the teeth of a rake, but 

 in some forms they may be teeth-bearing tubercles more or less 

 prominent, or the tubercles may simply be rough. These gill- 

 rakers are provided to prevent solid particles that might injure 

 the gills being carried into them ; in some cases they form a 

 perfect sieve, in others but a very inefficient one. The horny 

 rake-like teeth, which are often denticulated, are generally on 

 the outer side of the first branchial arch, and the tubercle forms 

 on the inside of this and on the inside and outside of the second 

 and third branchial arches, and the outside of the fourth. In 

 some fishes the rake-like gill-rakers are on all the branchial 

 arches. No account of the teeth in the pharynx of a fish would 

 be complete without noting the teeth that in many cases bristle 

 on the tubercles, or that line the inner side of the rake-like 

 protuberances. In the following descriptions, therefore, the gill- 

 rakers and the teeth on them will be noted, as well as those on 

 the pharyngeal bones themselves, and also the teeth that are 

 found along the surface of the epibranchials, yet distinct from 

 those on the epipharyngeal bones. 



Serranus gigas. Dusky Perch (Couch). Plate II., fig. 1. 



This fish is occasionally caught in British waters. The de- 

 tailed description of pharyngeal teeth may well begin with this 

 fish, for it possesses a perfect armoury of sharp teeth in the 

 posterior part of its mouth, as can be seen in the illustration. 

 On the first branchial arch the gill-rakers are short and stout ; 

 there are sixteen of them from the angle of the cerato- and epi- 

 branchial towards the end of the hypobranchial, and nine along 

 the epibranchial on the outer face of this arch. They all bear 

 teeth on the inner side. The one at the angle is the longest, and 

 has twenty sharp cardiform teeth on it ; its length is contained 

 about seven times in the length of the cerato- and hypo-branchial 

 of this arch. There are teeth bearing tubercles on the inner 

 face of this arch, which along the cerato- and hypo-branchial 

 correspond with the position of the outer gill-rakers. There are 



