60 SUPPLEMENT ON 



from three in carps to above thirty in elops, but commonly 

 there are seven, as in the common perch. Fish breathing 

 only by means of the water which they force out at the neck 

 after they have taken it in at the mouth, it passes between the 

 branchiae, which are formed like combs, usually four on each 

 side, and composed of a great quantity of laminae of a carti- 

 laginous and membranous nature, thin, narrow, forked, and 

 placed in regular files. These four branchiae are supported 

 by four pair of arches, adhering by their inferior extremities 

 to the two sides of a chain of intermediate little bones, which 

 is itself attached forward into the angle of the hyoid bone. 

 These arches also ascend in a curve backward, and fix their 

 other extremity by means of ligaments beneath the cranium. 

 The little intermediate bones are a sort of continuance of the 

 lingual bone ; they are usually three (No. 53, 54, 55), and 

 with the inferior pharyngeal (No. 56), give attachments to 

 the hyoid and the arches. The first three arches are com- 

 posed each of two pieces moving the one upon the other 

 (No. 57 and 58) ; the fourth consists but of a single bone 

 (No. 60). The superior portion (No. 61) is much shorter than 

 the other, and is simple in all, excepting in the first pair, 

 which, not having a pharyngeal bone to support, is usually 

 suspended from the cranium by a small stylus (No. 59). 

 The internal face of the arches is armed with teeth, or small 

 plates, or cones, and in some there is a row of teeth exter- 

 nally on the first pair (No. 63). 



The pharyngeal bones are placed at the entrance of the 

 oesophagus, immediately behind the branchial apparatus, for 

 the purpose of performing a second mastication, often more 

 powerful than the first, and accordingly in different species 

 they are armed with different kinds of teeth. There are 

 usually two inferior, and six superior ; the former (No. 56) 

 are in general two triangular plates, serving as a floor to the 

 pharynx ; or they turn in part round the oesophagus, or form 



