NOTES AND QUERIES. 



[Under this Department Heading queries relative to Anglin^ 



will be answered.] 



Ichthyology and Fish Culture, 



Fish Scales. 



[Extracts from a lecture delivered by J. W. Zaehns- 

 dorf, before the London, Eng., Piscatorial Society.] 



The roach angler fishes for roach. He 

 knows — or should know — a roach when he sees 

 one. Show him a roach scale, and ask him to 

 what fish it belongs. Can he tell you? Here 

 we have a roach scale. Unfortunately I have 

 not a rudd scale to show ; but the roach and 

 the rudd are so nearly alike that this scarcely 

 matters. Ask the sea fisherman to give you a 

 few scales of the cod. Most likely he will tell 

 you it hasn't any. Ask him for a few from the 

 eel. He will most probably reply, "Who ever 

 heard of 'em?" They are there, however, but 

 under the skin, and each species of eel has a 

 different scale. Here we have an eel skin 

 showing the curious formation of the scales 

 running at diverse angles, and here are a few 

 of the scales squeezed out and stained so as to 

 render them visible. Nevertheless, all fishes 

 provided with electric organs (those of the eel 

 family and the lamprey) are naked. It is very 

 curious that these fish should be minus scales 

 — a point which I am not at this moment pre- 

 pared to explain. 



Not only are different fish provided with 

 differently sliaped scales ; but those scales 

 which belong to the same fish vary in structure 

 according as they are found on this or that 

 part of the body. Here are the scales of the 

 jack. I would call your particular attention to 

 the curious lobes (if I may use the word) 

 which are attached to these scales. Here is a 

 scale with two lobes ; here are others with 

 three and four respectively — all from the same 

 fish ; and they are so disconnected at their 

 points that you can easily lift one lobe from 

 the other by means of a needle or a penknife. 

 For the purposes of strict comparison one should 

 take scales only from one particular spot of 

 each fish. This, however, it has been impossi- 

 ble for me to do in every instance. 



Fish scales are contained within the sub- 

 stance of the skin, and are not merely attached 

 to it by one end, as appears to be the case. In 

 most of our common or fresh water fish, such 

 as the roach, etc., the scale projects beyond 

 the level of the skin, and the projecting portion 

 is covered by a thin layer of skin. When the 

 scales are scraped off the body, this layer, with 

 its beautiful pigment cells, is usually found 

 adhering to it. In some fishes, as the cod and 

 eel, the scales are entirely sunk below the 

 surface. The scales of different parts of the 

 body are of different sizes, and those down the 

 side, forming the lateral line, are pierced 

 through the centre with openings, or ducts, 

 to allow the escape of a fluid which lubricates 

 the skin beneath, without which fish will very 

 soon die. The lateral line runs from the head 

 to the tail, sometimes reaching the caudal fin, 

 sometimes stopping short of it, sometimes 

 advancing over its rays. Certain species have 

 several lateral lines, an upper one following 

 the dorsal, a lower one the abdominal outline 

 whilst a third runs along the middle as usual. 

 The scales of the lateral line are sometimes 

 larger than the others, sometimes smaller. 

 Occasionally there are no other scales than 

 these, the rest of the body being naked. 

 Therefore the lateral line scales may be viewed 

 as the most important. 



There are four denominations of scales men- 

 tioned by Agassiz — the cycloid, the stenoid, the 

 granoid, and the placoid. This classification 

 has been proved by living scientists to be not 

 perfectly accurate, but for the sake of conven- 

 ience I shall adopt this classification tonight, as 

 being quite near enough for my purpose, see- 

 ing that 1 wished to seize upon general princi- 

 ciples rather than detached instances. The 

 cycloid and the stenoid include all the most 

 common forms of scales, and are marked with 

 circular or concentric rings. By steeping in 

 water, the several layers, or laminae, of which 



