PHARYNGEAL TEETH OF FISHES. 101 



Polynemid^;. 

 Polynemus tetradactylus is known and appreciated as a table 

 fish in Calcutta as the "Mangoe Fish," and also as the " Tapsi 

 Machli," the latter being its native name. It has seven long 

 horny gill-rakers on the first cerato-hypobranchial arch, with 

 five on the epibranchial. The longest equals the depth of the 

 gill-laniinse below it. These gill-rakers all carry teeth. The 

 inside of the first arch has only three short horny gill-rakers. 

 The second and third arches have small flat tubercles for gill- 

 rakers, but only on the cerato portion, and on both sides of 

 these arches. The fourth arch has a few similar but even 

 smaller tubercles on its outer side only. The whole surface 

 of these arches, tubercles and all, is covered with minute 

 villiform teeth, which extend also to the surface of the basi- 

 branchials and on to the tongue. The upper pharyngeal teeth 

 consist of a small elongated group on the upper portion of each 

 of the first epibranchials, also a longer group on the heads of 

 each of the second epibranchials, with minute teeth extending 

 along the rest of, the limb ; a triangular group on the heads 

 of the third epibranchials, with teeth also extending down the 

 limb, and an irregularly shaped group, square at the top and 

 rounded at its lower part, on the heads of the fourth epi- 

 branchials ; below this last group, separate from it but still 

 on the fourth epibranchial, is a small triangular group. All 

 the teeth on the third and fourth epibranchials are cardiform. 

 The lower pharyngeal teeth are in two elongated groups, on the 

 fifth arch making a broad V in the mouth, but separated at the 

 apex. 



Ophiocephalidje. 



Ophiocephalus marulius, called the " Murrul " in India, has 

 fourteen tubercle gill-rakers on the first cerato-hypobranchial, 

 with one on the epibranchial of a large size. There are five 

 tubercles behind the angle also, at the base of the accessory 

 breathing apparatus. All the other gill-rakers are also tubercle- 

 shaped ; they fit closely into one another and form a good 

 filter. The tubercles all carry minute teeth. The upper 

 pharyngeal teeth consist of a narrow group on the head of 

 the second epibranchial, of minute cardiform teeth, and a fairly 

 large group on the heads of the third and fourth epibranchials, 



