Page:Popular Science Monthly Volume 11.djvu/555

Rh apparatus is very peculiar, being composed of seven pouches on each side, which receive water from the lateral openings of a canal distinct from the œsophagus, and discharge the same through seven branchial openings on each side of the neck; and their mouth and tongue are more strange than their breathing apparatus." The mouth is round, and the tongue moves forward and backward in it like a piston, thus enabling the animal to produce a vacuum to fix itself firmly to a stone or any other body in the water.

As we get near the bottom of the scale in the examination of fishes, we find forms which, so far as their general outline is concerned, give no intimation of their true affinities. The myxines, or hags (Fig. 32), are of this sort: small fishes which have the general aspect of



worms, but whose plan of structure shows them to be vertebrates, and whose circular mouth and piston-like tongue ally them to the lampreys.

And at the very bottom of the group of fishes we find the little amphioxus, or lancelet (Fig. 33); and how wide is the gap between this soft, nearly transparent vertebrate, without teeth or jaws, with out skeleton or real head, and with only a mere slit for a mouth, and the typical fish as we see it in the shad, the cod, and the salmon! So little does the amphioxus appear like even a vertebrate, that Pallas, the naturalist who first described it, thought that it was some sort of slug or snail.

These strange forms of fishes are facts; and the important question is, What do they mean? What has caused them? What are they for? Will they continue? These and other questions quickly suggest themselves, and are easily asked; but are not so easily answered.

The whole subject of the origin and meaning of organic forms is a very important one. It is not so narrow as indicated by the questions asked above about the queer forms of certain fishes; but it is a subject which embraces inquiry into the origin and full significance of all organic forms upon the earth and within its crust.

Are these fishes and all other organic forms just as they were created? The creationist says "Yes;" the evolutionist says "No." Suppose we admit the doctrine that they were all created as they now appear what does it mean that there are 15,000 specific forms of fishes, and that a thousand, or two thousand, more or less, are of these outré forms described above? Can any one give a satisfactory