Page:Popular Science Monthly Volume 63.djvu/39

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placed in an aquarium in water slightly warmed. In a few moments slight movements of the fish could be seen through the papery shell; and upon lifting out the earthen block and touching the cocoon, a distinct croaking sound was heard several times. Replaced in water, the capsule soon softened and ruptured like wet paper, and for a moment a glimpse was had of the fish tightly rolled up, with its tail folded over the head and only a single thread-like limb protruded. This, however, was but for a moment, for with an energetic squirm the animal liberated itself and sank to the bottom of the aquarium. For a moment it lay motionless, then swam briskly around the aquarium, coming to the surface several times and gulping air. At this time it showed the crimson flush of blood in the tail region where, according to Wiedersheim, the skin aids the lung as a respiratory organ. The fish, as one might indeed have inferred from the size of the burrow in the clod of earth, proved to be small, measuring a little over five inches in length. It was, however, larger than one would have estimated from the diameter of the tubular opening and from the actual size of the cocoon, the latter measuring about two inches in length and one inch in thickness. In Fig. 2 is shown the remains of the cocoon after the escape of the fish, the upper portion of the papery case alone being preserved.

From the small size of the fish this was possibly its first season of æstivation. How long it had been out of the water was not known, but

PSM V63 D039 Lung fish.png

Fig. 3. Lung-fish, Protopterus. Resting position in aquarium.

certainly this was a matter of several months. I have, indeed, learned from Dr. Forbes that a fish will sometimes survive a period of eight months out of water.

Shortly after its release from the cocoon the writer's colleague, Dr. Edward Learning, took a number of photographs of the fish, some of which are shown herewith, to give a graphic idea of its appearance and unfish-like movements (Figs. 3 to 6). In side view, Fig. 3, the fish is shown in a position of rest, its body resting upon the bottom, its long, paired extremities extended out, braced against the glass side of the aquarium. When moving, however, the fish would