On the Scales of Fishes. 251 



root must proceed to a larger extent, and perhaps more rapidly 

 than toward the free border. The raised lines or sections 

 which proceed toward this covered portion of the scale, and to 

 which reference has already been made, are sometimes carried 

 out in a crenated form, as in the sea-bream, and con- 

 spicuously in the perch, as also in the Labridce or wrasses, where 

 the common wrass, Labrus balanus shows a large number of 

 them, together with an extensive disk ; but in some 

 instances those on the side are more lengthened out, and in 

 others, as the pike, JEsox Indus, and piper, Trigla piper, 

 where the number is only three, the middle segment extends 

 beyond the others. The atherine, Atherina presbyter, can 

 scarcely be said to have more than one, but the scale of this 

 fish is marked with a structure that forms a special character in 

 another genus, the Clupeidoe, the herring, and pilchard, to 

 which, therefore, that fish may seem to bear some distant 

 affinity. It consists in some well marked hard lines, which, 

 behind the disk, pass from one border to the other, but 

 apparently with particular reference to a middle longitudinal 

 depression. These somewhat waved crossing lines are so 

 formed in their intimate structure, that when the scales are in 

 partial decomposition, the separated portions cease to adhere 

 to each other, except where they are brought together at the 

 longitudinal depression which proceeds from the disk. 



The scales of the lateral line are those only which require 

 further general remark, and their organization is for the par- 

 ticular purpose of being the channels through which a lubri- 

 cating fluid shall be conveyed from a secreting order of vessels 

 beneath them to the outer surface. This channel usually lies 

 along the middle of the scale that bears it, with its opening 

 directed toward the tail of the fish • at near its extremity this 

 is often divided into branches, as in the case in the Scicena; but 

 even in the same fish all these branched channels are not 

 exactly alike, and in the sea-bream they have some curious 

 arrangements of direction ; their direction being on the upper 

 border of the lateral line, but covered by the scale next before 

 each one, yet through which it may be seen, while the orifice 

 points to the lower border, where it is bent a little, by which 

 means the thin edge of the coverring scale slightly covers 

 the order of the tube. It is thus that the lower side of 

 the tube is above the apparent lateral line, although close 

 to it. 



That the conclusions here advanced on the intimate structure 

 of the scales of fishes, and their mode of growth, as well as the 

 affinity of their structure, have not been obtained from very 

 limited observation, will appear from the following list of 

 species that have been subjected to examination; which with 



