THE PHARYNGEAL TEETH OF FISHES. 137 



last ones are very minute ; they carry teeth on their inner 

 margins. On the inner face of the first branchial arch there 

 are tubercles, as also on the inner and outer faces of the second 

 and third arches, and on the outer face of the fourth arch. The 

 upper pharyngeal teeth show as two patches, the upper a small 

 narrow patch with small cardiform teeth, the lower of the two 

 as a circular patch with cardiform teeth specially strong at the 

 lower portion of the patch. The lower pharyngeal teeth are 

 in two triangular shaped patches, with a row of strong cardiform 

 teeth along the margins on each side at the middle of the mouth, 

 the other teeth being smaller. A narrow division runs up be- 

 tween the two patches of teeth. 



Onus communis. Fig. 4 (p. 135). 

 This fish has seven tubercular gill-rakers on the first arch 

 cerato-hypobranchials ; these carry teeth. The inside of the 

 first arch and the other arches have tubercles on them which 

 are toothed. The upper pharyngeal teeth, which are cardiform, 

 are in two patches, with a third small narrow piece on the 

 inner edge of the third epibranchial, which has villiform teeth. 

 The lower pharyngeals in two patches have minute cardiform 

 teeth, which are more prominent along the middle portion of 

 the mouth. The two patches meet across the middle of the 

 mouth at the anterior ends. 



Onus tricirratus. The Three-bearded Eockling. 

 The upper and lower pharyngeals are as in the last men- 

 tioned, the junction of the two portions being niore complete in 

 this fish. The food of the Eocklings is mostly composed of 

 crustaceans ; they also eat annelids, starfish, and other smaller 

 fishes than themselves. 



Gadus poutassou. Fig. 5 (p. 135). 

 This fish has twenty-three horny upstanding gill-rakers from 

 the angle of the branchial arch to the end of the first hypo- 

 branchial arch, the one at the angle being the longest, and its 

 length nearly one-fourth of the length from its base to the end 

 of the hypobranchial of the same arch ; these gill-rakers 

 diminish in size fairly evenly till the last minute one is 

 reached ; there are six on the epibranchial. The inside of the 

 Zool. 4th ser. vol. XV.. April, 1911. M 



