THE BATRACHIANS, OR AMPHIBIANS.
Among the many wonders of Nature, none is more interesting than those forms which serve to connect the great groups of vertebrate animals, by bridging over what otherwise would seem like impassable chasms.
Between the birds and the reptiles there is a fossil bird, called the Archæopteryx, with a long, vertebrated, lizard-like tail, which is covered with feathers, and the Hesperornis, a water bird with teeth, but no wings, which inhabited the shores of the great western lake which has already yielded to American paleontologists a great number of most remarkable fossil forms.
Between the reptiles and the fishes, stretches a wonderful chain of living links by which those two Classes of vertebrates are so closely and unbrokenly united, and by such an array of forms, that they constitute an independent Class, the Batrachia, or Amphibia. In the transition from water to land, from fins and gills to legs and lungs, Nature has made some strange combinations. In some instances the fins, legs, lungs and gills have become so mixed that several notable misfits have resulted, and in some cases we see gills and legs going together, while in other lungs and fins are associated.
The Reptile House contains about two dozen species of Amphibians, and it is reasonably certain that this number will be maintained and increased. They are to be found in small aquarium cases, ranged along the south side and eastern end of the Main Hall.
The Bullfrog, (Rana catesbiana), is a fair representative of the Batrachians which stand nearest to the true land-going reptiles. During the early stages of its existence it is in turn, a fin-tailed tadpole with no legs, a short-tailed tadpole with a pair of front legs, a shorter-tailed tadpole with four legs, and finally a fully-developed, land-going frog with a voice like a small bull, and no tail whatever. Of the genus Rana, there are five species in the eastern United States, several of which inhabit the Zoological Park.
The Wood Frog, (Rana sylvatica), is frequently seen in moist valleys in the Zoological Park, where its chocolate brown back so closely matches the color of the dead leaves and moist earth; it is difficult to find, save when it takes one of its flying leaps. The specimens shown were taken near the Beaver Pond.
The Tree Frog, (Hyla pickeringi), is the commonest of the queer little tree-loving species which are so easy to hear, and so difficult to find. In spring their voices are the first to be heard in the swamps. The Zoological Park is full of Hylas, and their cheerful piping is heard at all seasons, especially in dry midsummer, when dark storm-clouds gather and promise rain.
The Common Toad, (Bufo lentiginosus), is found in the Zoological Park, though not in such abundance as the two preceding species.
Among the most remarkable creatures in the Reptile House are the specimens of Smooth-Clawed Frog, (Xenopus laevis), from Africa and The Surinam Toad, (Pipa americana). Both of these species are strictly aquatic and have broadly palmated hind feet. The Surinam Toad comes from Dutch Guiana. It is unique in its breeding habits. The male collects the eggs and places them on the female’s back where they are engulfed in large folds of the skin, which form cells in which the metamorphosis occurs.
The Spotted Salamander, (Salamandra maculosa), because of its broad, bright yellow bands and blotches, laid on a rich, dark-brown body color, is one of the most showy of all Amphibians. It comes from Europe, and being much prized in collections, it frequently passes through the hands of dealers in reptiles. Its skin is very moist and clammy, which gives the creature the appearance of having been varnished. This is the creature which is supposed to be able to withstand fire—a belief which is purely imaginative.
The Tiger Salamander or Axolotl, (Amblystoma tigrinum), is a widely different creature from the preceding. It is found throughout the greater portion of the North American continent, and as far south as Central Mexico. Thirteen other species of the genus Amblystoma are found in North America and Mexico. In the matter of “harmonizing with environment,” the Amblystoma is one of the most remarkable creatures in existence. In its larval stage (corresponding with the tadpole stage of a frog), this animal possesses external gills, red and sponge-like in appearance, and its tail has a fin-like edge above and below, like the tail of an eel.
METAMORPHOSIS OF THE LEOPARD FROG.
So long as this larval creature remains in water, its external gills remain and do duty, and the larval stage continues indefinitely. Remove it from water, or let its home pool dry up, and, presto! its gills dry up, its tail loses its fin-like edges, and the creature goes about on land, breathing air instead of water, with lungs instead of gills.
The “Water-Dog” or “Hellbender,” (Cryptobranchus allegheniensis), is a salamander-like amphibian, from 18 to 22 inches long when adult, found more frequently in Pennsylvania than elsewhere. They are said to be very tenacious of life, and voracious in their food habits, feeding on worms, minnows and crayfish, and often taking the hook of the fisherman in quest of that most repulsive of all American fishes, the cat-fish. Between cat-fish and water-dog there would seem to be small choice. Mr. William Frear offers this testimony in regard to the tenacity of life of this creature:
“One specimen, about 18 inches in length, which had lain on the ground exposed to a summer sun for 48 hours, was brought to the museum, and left lying a day longer before it was placed in alcohol. The day following, desiring to note a few points of structure, I removed it from the alcohol in which it had been completely submerged for at least 20 hours, and had no sooner placed in on the table than it began to open its big mouth, vigorously sway its tail to and fro, and give other undoubted signs of vitality.”
The Congo Snake, or Amphiuma, (Amphiuma means), is a creature which closely resembles a thick-tailed snake. A close examination, however, discloses a tiny pair of front legs; and far back, well toward the end of the tail, a small pair of hind legs appear. These are about as valuable to the animal as the tiger’s clavicle is to him. There are but two species belonging to this strange genus, both of which are found in the stagnant waters of our southeastern states. Still lower than the amphiuma, is The Mud Eel, (Siren lacertina), of the southeastern quarter of the United States, which possesses small external gills, and only one pair of legs, which are in front.
The Menobranchus, or Mud Puppy, (Necturus maculatus), possesses external gills and four legs, and inhabits many of the rivers of Ohio, Pennsylvania, Indiana, the great lakes and also the lakes of northern New York. It is often taken in fisherman’s nets.