THE

POPULAR

SCIENCE

MONTHLY.

MAY, 1877.

SOME

GAR-PIKES, OLD AND YOUNG.

BY PROFESSOR BURT G. WILDER,

OF CORNELL UNIVERSITY.

I.

OME 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 garpikes do, it is necessary to explain what they are.

FIG. 1.-THE SHORT-NOSED GAR-PIKE (Lepidosteus platystomus),

Nearly adult, one-fourth natural length. O, the gill cover, or operculum. P, the pectoral, and Fe, 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. Xindicates 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 backbone made up of a series of segments or vertebrae. 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

VOL. XI.-1

the stomach, intestine, heart, and other organs of vegetative life. This is shown in Fig. 3.

Let us now go one step further and learn what kind of a vertebrate is the gar-pike. At present the most natural primary subdivi sion of the branch seems to be into three great groups. The highest

FIG. 2.-PART OF THE SIDE OF THE BODY OF Lepidosteus platystomus, Natural size, showing the arrangement of the enameled scales. Below is an outline of a single scale; the point is covered by the scale in front.

is the Mammalia, comprising our common quadrupeds, also bats, monkeys and men, seals and whales. The females of all these bring forth their young alive, and nourish them with milk.

Next come the Sauropsida, including birds, turtles, crocodiles, lizards, and snakes. Lastly, the Ichthyopsida, embracing the Batrachians (frogs, toads, and salamanders), and all other vertebrates.

Evidently, our gar-pike is neither a mammal nor a bird, a turtle, a snake, nor a lizard. It does look a little like an alligator, but it has not only fins and scales, but also gills, which are not known to exist in any reptile; while all the Ichthyopsida have gills during at least a part of their lives. The gar-pike is neither a frog nor a toad; it has scales and fin-rays unlike salamanders. Why, then, not call it a fish?

FIG. 3.-CROSS-SECTION (NATURAL SIZE) OF THE SHORT-NOSED GAR-PIKE (Lepidosteus platystomus),

Showing the general arrangement of the organs which is characteristic of vertebrates. The section is made in front of the ventral fins at the point indicated by X on Fig. 1. The cut surface is looked at from behind. Near the middle is the vertebral column or backbone (VC). Above it is the spinal cord (SC), surrounded by bony walls. Below are the abdominal viscera. A is the median aorta, V V the lateral veins. MA is the median channel of the air-bladder, and LA, LA, are its lateral chambers. The cavity of the stomach (A) is on the left, and the liver (L), with two veins, on the right. 0, 0 are the two ovaries, of which the left lies farther forward so that its section is smaller. The whole is surrounded by the muscular walls of the body (M, M, M, M), and this again is covered by the plates of the skin.

Because, unfortunately, we are not sure that there are any "fishes." The terms "beast, bird, and fish," notwithstanding common usage and the sanction of Scripture, are devoid of scientific accuracy. For "beast" includes turtles and alligators, and excludes the aquatic mammals, whales, porpoises, manatee, and dugong. "Bird" includes. bats and pterodactyls, and excludes the ostriches and penguins, which cannot fly. So "fish" is not only held by some persons to embrace the aquatic mammals, but also, when employed in a stricter sense, it includes forms differing among themselves in many important points. At any rate, the "fish-like vertebrates" present the following wellmarked groups:

1. Amphioxus lanceolatus; the lancelet. A single genus with perhaps a single species, but so peculiar as to have received the following appellations: Branchiostoma, Cirrostomi, Pharyngobranchii, Leptocardia, Acrania, Entomocrania, Dermopteri.

2. Myzonts, or Marsipobranchii; the hag-fishes and lamprey-eels. 3. Plagiostomes, or Elasmobranchii; sharks and skates.

4. Holocephala; the Chimera and Callorhynchus.

5. Ganoids; the sturgeons (Acipenser and Scaphyrhynchus); the spoonbill (Polyodon); the mud-fish (Amia); the gar-pike (Lepidosteus); and the Polypterus and Calamoichthys of Africa, with many fossil forms.

6. Dipnoans; the mud-fishes of Africa, South America, and Australia (Protopterus, Lepidosiren, and Ceratodus).

All of the above were formerly, and are now popularly, regarded as fishes.

But the fishes proper, or ordinary fishes, are now called:

7. Teleosts; the perch, salmon, cod, mackerel, and all others not included within the other six groups.

Some have included Amphioxus with the Myzonts; others the Plagiostomes with the Ganoids. The most natural combination seems to be that of the Ganoids with the Teleosts; and to this larger group the term Pisces has been applied. But for the present it is safer to recognize the distinctions, and to make our generalizations

more exact.

What, then, is a gar-pike? Is it a Ganoid or a Teleost? Curiously enough, the prefix "gar" (signifying a dart or pointed weapon) is employed to designate two fishes, of which one (Belone) is a marine Teleost, and the other (Lepidosteus) is a fluviatile Ganoid. Both have long jaws with sharp teeth, but in other respects they are very unlike. It will be better to call Belone the "gar-fish" and Lepidosteus the gar-pike.'

The general appearance of the gar-pike is sufficiently indicated by

1 These common names are very perplexing. Thus the true pike is Esox. The name dog-fish is popularly applied to Menobranchus, a batrachian; to Amia, a ganoid; and to Acanthias, a shark.

the figure. The body is an elongated cylinder covered with hard and shining scales closely joined, and leaving as vulnerable points only the throat and gills, the eyes, and the parts just under the pectoral fins. The tail is moderate in size and rounded, the longest rays a little above the middle, so that it is not quite symmetrical. Upon the hinder part of the back is the dorsal fin, and below the dorsal an anal fin, immediately in front of which is the vent or outlet of the alimentary canal. The paired fins, pectoral and ventral, occupy the places natural to them as representatives of the anterior and posterior limbs of salamanders and alligators.

The length of the head varies in the different species, but, whether longer or shorter, the jaws are furnished with rows of very sharp and closely-set teeth. The apparent form of these teeth is a simple elongated cone; but it has been shown by Prof. Jeffries Wyman that their surface is really deeply folded, so that a cross-section resembles that of the teeth of the curious fossil Batrachians, called, for that reason, Labyrinthodonts. The eyes are of moderate size. As with ordinary fishes, the ears do not appear externally. The nostrils are two pair of small holes at the tip of the snout, communicating with an olfactory sac on each side; the lining of this sac presents one median longitudinal and many transverse folds.

The genus Lepidosteus, according to Huxley, has not been found earlier than the Tertiary rocks; although the family Lepidosteida is represented by more or less numerous genera as far back as the Carboniferous and perhaps (by Cheirolepis) in the Devonian.

True gar-pikes are not found in Europe, Asia, Africa, or Australia, or in South America; while in North America they seem to be nearly confined to the Mississippi River and its tributaries, and the Great Lakes.'

Prof. Poey has also recorded the existence of a gar-pike in Cuba, a fact which is interesting, not as an indication of "manifest destiny," but as a memorial of the supposed ancient connection between the West India Islands and our continent. None have been found in saltwater, and the writer has no knowledge as to how far they enter the mixed water at the mouth of the Mississippi; but their tenacity of life encourages the belief that they might possibly adapt themselves to the ocean. Their introduction into New England waters would afford to Eastern zoologists the much-desired opportunity of studying their development, of which nothing whatever is known.

We must now inquire whether there are more than one species of Lepidosteus.

Unfortunately, this question involves several others. For the genus Lepidosteus, established by Lacepede for the single species

1 A few examples have been taken in Cayuga Lake, in Central New York, having probably entered by the canal at its northern end; it is said to occur in the Susquehanna River, Pennsylvania. It is lately reported that a species has been found in China.