Page:Popular Science Monthly Volume 11.djvu/11

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THE

POPULAR SCIENCE

MONTHLY.



MAY, 1877.



GAR-PIKES, OLD AND YOUNG.
By Professor BURT G. WILDER,
OF CORNELL UNIVERSITY.
I.

SOME readers of The Popular Science Monthly may never have seen gar-pikes, or even heard of them. The word does not occur in some of the dictionaries, and the animals themselves are found alive only in certain parts of the world. So, before telling what gar-pikes do, it is necessary to explain what they are.

PSM V11 D011 Short nosed gar pike.jpg
Fig. 1.—The Short-nosed Gar-Pike (Lepidosteus plaiysiomus)
Nearly adult, one-fourth natural length. O, the gill cover, or operculum. P, the pectoral, and Ve, the ventral, fin of the left side. D and A, the dorsal and anal fins. DF and VF, the "fulcra" which cover the dorsal and ventral borders of the root of the tail. X indicates the point where the section shown in Fig. 3 was made. The scales are shown in the next figure.

In the first place, the gar-pike is not a weapon, but a vertebrated animal. The vertebrates include all animals having a spine or back-bone made up of a series of segments or vertebræ. But this common definition is not wholly accurate. For the very young of man and monkeys, quadrupeds and birds, reptiles and fishes, have no skeleton at all; and some of the lowest fishes, the Amphioxus and the lamprey-eels, have no bones. So the vertebrates are now said to include all animals having a longitudinal axis or spine (whether membrane, cartilage, or bone) separating an upper or dorsal cavity, containing the spinal cord and brain, from a lower or ventral cavity, containing