138 THE ZOOLOGIST. 



THE PHARYNGEAL TEETH OF FISHES. 

 By Colonel G. E. Shepherd (Indian Army). 



(Continued from vol. xvi. p. 459.) 



Characinid^;. 



The Characinidce are furnished with formidable teeth in their 

 jaws ; their pharyngeal teeth, however, are feeble in comparison. 



Alestes nurse, a Nilotic fish, has seventeen long, fine, horny 

 gill-rakers on the first cerato-hypobranchial arch, and thirteen 

 on the epibranchial. The inner and outer sides of the other 

 arches are thickly set with the same kind of delicate gill-rakers, 

 also carried up to the top of the epibranchials, those on the 

 outer sides being a trifle longer than those on the inner side. 

 No pharyngeal teeth apparent ; a thickening of the mucous 

 membrane into a seeming boss where the first, second, and third 

 hypobranchials join the basibranchials, and the surface at these 

 places covered with papillae. 



Citharinus citharus, a Nilotic fish, has a number of small 

 bristle-like gill-rakers on the inside top of the first three 

 branchial arches extending up the epibranchials. No pharyngeal 

 teeth apparent. 



Distickodus niloticus, as its name implies, a Nilotic fish, has 

 minute hair-like gill-rakers standing up both on the inner and 

 outer sides of the branchial arches, which are also carried up 

 along the epibranchials to their upper part. No pharyngeal 

 teeth apparent. 



Erythrinus salmoneus, from British Guiana, has four, short, 

 horny gill-rakers, followed by six tubercular lumps on the first 

 cerato-hypobranchial arch, with one short gill-raker and some 

 tubercles on the first epibranchial. These gill-rakers and 

 tubercles bear teeth. The other arches have horny tubercles, 

 but not toothed. The upper pharyngeal teeth are minute, and 

 placed on the heads of the second, third, and fourth epi- 

 branchials. The lower pharyngeals are similarly minute. 





