PHARYNGEAL TEETH OF FISHES. 99 



group of villiform teeth, occupying the whole floor of the gullet. 

 The lower pharyngeal bones are united. 



Ammodytidje. 

 Ammodytes lanceolatus, the Greater Launce, also called the 

 " Greater Sand Eel," has nineteen long, horny gill-rakers on 

 the first branchial arch, cerato-hypobranchial portion ; the 

 length of the longest equals the depth of the gill-laminae below 

 it ; there are four on the epibranchial. The second and third 

 arches have similar but shorter gill-rakers on their outer sides, 

 whilst on the fourth arch they are shorter still. The upper and 

 lower pharyngeal teeth are very minute, barely but just 

 palpable to the touch ; under the microscope they show as 



cardiform teeth. 



Athebinid^;. 



Atherinichthys argentinense, called the " Pajerry " at Buenos 

 Aires, has thirty-three long horny gill-rakers on the first cerato- 

 hypobranchial arch, with nine on the epibranchial. They all 

 carry teeth. The first thirteen along the cerato portion count- 

 ing from the angle have their tips turned backwards, as also are 

 the tips of the first two on the epibranchial. The length of the 

 longest gill-raker is equal to the depth of the gill-laminae below 

 it. The inside of the first arch, and both sides of the second, 

 third, and fourth arches all carry numerous short horny gill- 

 rakers bristling with teeth ; these gill-rakers fit closely between 

 themselves and form a very good filter. The upper pharyngeal 

 teeth consist of a long narrow group of minute cardiform teeth 

 on the limb of the third epibranchial, and two long, narrow, 

 roughly elliptical shields on each of the heads of the third and 

 fourth epibranchials, bearing strong conical teeth in the upper 

 half of the shield, with rather smaller conical teeth in the lower 

 half. The lower pharyngeal teeth are in two elongated groups 

 with strong conical teeth at the back part, those in the front 

 part being smaller. There is a marked division in the middle 

 line between the two sets. There is a small group forming four 

 sets of minute teeth, each set apart, at the junction of the 

 second and third hypobranchials with the basibranchials, and 

 also one group stretching across the basibranchials at the junction 

 of the third and fourth arches. (Fig. I.) 



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