13KAZIL1AN PEKCOPH1B. 



Urazilidnus. 



The third series of scales are named Ctenoid, or comb-like scales, on account of tha 

 toothed projections in their posterior edge. The beautiful scales of the Perch, so largely 

 used in the manufacture of feminine ornaments, are familiar examples of ctenoid 

 scales. The last class are the Cycloid, or rounded scales without teeth, such as those 

 of the carp. 



On careful examination, the scales are found to be composed of two layers, which 

 can be separated by careful manipulation, and their structure is permeated with channels, 

 either partially closed so as to form grooves, or wholly so, and then become tubes. The 

 comparatively straight lines which radiate towards the circumference, and the wavy 

 lines which are drawn concentrically and cover almost the entire scale, can be referred 

 to a common spot, called technically the " focus." This spot cannot rightly be termed 

 the centre, because it is of variable dimensions, and, moreover, is seldom if ever placed 

 exactly in the middle of the scale. 



Many scales throw out strong tooth-like projections, which in point of fact are the 

 teeth of the external skin, and in some species, such as several of the dog-fish, are of 

 crystalline hardness. In some fish, "such as the stickleback, a few of these processes 

 of the skin are developed into long sword-like weapons ; in others, such as the trunk- 

 fish, they are fused together, and form a continuous bony envelope to the body, pierced 

 for the protrusion of the tail and fins ; in some, of which the diodons are good examples, 

 they cover the body with an array of projecting spikes, like the quills of the hedgehog 

 or porcupine, and in others, such as the sturgeons, are arranged in rows of bony plates 

 along the body. 



WE return to the species now under consideration. 



The BRAZILIAN PEECOPIIIS is found upon the coasts of Brazil, and is apparently the 

 sole representative of the genus in which it has been placed. The first dorsal fin is 

 very sma,ll in proportion to the second, and the space between them is about equal to the 

 length of the first dorsal The ventral fins are set very far forward, being placed under 

 j,he throat. The lower jaw projects considerably beyond the upper, and the cleft of the 



