THE PHARYNGEAL TEETH OF FISHES. 141 



of the first arch is devoid of gill-rakers, and there are only two 

 on the epibranchial. These gill-rakers are smooth to the touch. 

 The other arches are wanting in gill-rakers. The upper pharyn- 

 geal teeth show as four distinct patches — one long narrow one 

 at the summit of the second epibranchial, a larger one at the 

 end of the third epibranchial, with a smaller patch along the 

 same towards the angle, and a fourth attached to the fourth epi- 

 branchial. The lower pharyngeals are two long narrow patches. 

 From the forward end of these along the basi-branchials there 

 are a pair of patches of villiform teeth between the junctions of 

 the basi-branchials with the second and third hypobranchials, 

 the patches meeting close together in the median line. Another 

 pair of patches, forward of the last two, starting from the junc- 

 tion of the second hypo- with the basi-branchial, are carried 

 along to the junction of the hypo-hyal with the os glossa. These 

 have a smooth portion in the middle line ; they are covered with 

 villiform teeth. 



Seriola dumerilii. Yellow-tail. Fig. 4 (p. 139). 

 This fish has twelve horny gill-rakers along the outside of 

 the first cerato-hypobranchials ; the longest one at the angle is 

 contained some five times in the length of these two bones. 

 There are three on the epibranchial. These gill-rakers have 

 minute teeth on them. The inner side of the first arch has 

 conspicuous tubercle gill-rakers on it, and there are very small 

 inconspicuous ones on the inner sides of the second and third 

 arches, with none at all on the outer sides. The surface of the 

 skin of the arches is covered with a roughness that can be felt by 

 the finger if passed over it in the direction against the swallow. 

 The upper pharyngeal teeth show as three patches of teeth • 

 sharp little teeth if the finger is drawn against them, smooth if 

 the finger is passed in the direction of the swallow. The lower 

 pharyngeals carry two long narrow patches of t^eth ; minute 

 villiform teeth are found along the upper surface of the basi- 

 branchials, and continue to the tip of the tongue. 



Naucrates ductor. The Pilot-fish. 

 The upper pharyngeal teeth are cardiform but minute, and 

 80 are the lower pharyngeal teeth. 



