388 THE ZOOLOGIST. 



Balistid^;. 



Batistes capriscus (the File-fish, also called "Trigger-fish") 

 occasionally found in the South of England, plentiful in the 

 Mediterranean, has twenty-four horny gill-rakers on the first 

 cerato-hypobranchial arch, with five on the epibranchial part ; 

 on the other arches there are tubercles. The upper pharyngeal 

 teeth are cardiform, and set far back in the pharynx. The lower 

 pharyngeal teeth are a few cardiform teeth in the middle line of 

 the floor of the gullet. This fish feeds on the coral insects and on 

 Mollusca, which its powerful front teeth enable it to do. Fig. IV., 2. 



Balistes erythrodon, from the Indian Ocean, has twenty-six 

 horny gill-rakers on the first branchial arch from the angle to 

 the end of the hypobranchial, and six on the first epibranchial. 

 The other gill-rakers consist of tubercles, but not quite such 

 pointed ones as in the next to be described fish. The upper 

 pharyngeal teeth are cardiform and not very numerous. The 

 lower pharyngeal teeth are in two rows on the margins of the 

 lower pharyngeal bone ; they are small, and can be felt better 

 than seen. 



Balistes niger, from the Indian Ocean, has twenty fine horny 

 gill-rakers along the first cerato-hypobranchial, with eight along 

 its epibranchial ; the other arches carry tubercle gill-rakers of 

 an elongated pointed shape that fit in alternately and form a 

 very close filter. The pharyngeal teeth are cardiform, and set 

 far back in the gullet. 



Cichlid^:. 



Cichlosoma bimaculatum (called the " Putwa " at Demerara) 

 has five short, upstanding gill-rakers, the longest about one- 

 fourth the depth of the gill-lamina below it, on the first cerato- 

 hypobranchial arch, with one on the first epibranchial. There 

 are gill-rakers on each side of the other arches. The upper 

 pharyngeal teeth are in two small patches, speckled over with 

 little brown teeth, on the heads of the third and fourth epi- 

 branchials. There are minute brown teeth for the lower 

 pharyngeals, speckled over a triangular patch. 



Crenicichla saxatilis, from British Guiana, has on the first 

 cerato-hypobranchial arch seven short upstanding gill-rakers 

 which bear teeth, with two on its epibranchial. The other arches 

 have gill- rakers inside and outside. The upper pharyngeal teeth 

 consist of an elongated patch, on the third epibranchial, of small 



