An explorer in the desolate heights of the Santa Marta mountains in northeastern Colombia, fog-wrapped and 10,000 feet above sea level, may see a flock of sheep grazing placidly among rocks ahead of him. Then, looking the other way, he may see an assembly of cowled, robed priests, apparently in the midst of some weird ecclesiastical ceremony. But when he reaches the places where he thought he saw these things there are neither sheep nor priests. He finds instead two strange varieties of the aster family, both among the real curiosities of the plant kingdom. The vegetable sheep are bushy plants which grow on nearly barren ground near the mountain tops. The individual plant consists of thickly branched stems, about the size of a human finger, bearing many layers of leaves covered with wool-like hairs. Sometimes these leaves are so thick that the point of a pencil cannot be thrust through them. Some of the plants may be as large as a living-room sofa. The extreme compactness of these plants and their dense covering of hairs is an adaptation to the hostile conditions under which they must live. The habitat consists of rocky slopes where the hot, dry winds of summer and the snows, low temperature and violent gales of winter expose them to a perpetual alternation of desert and Arctic conditions. In the same general region are the monk plants, belonging to a different family, who have responded in the same way to similar conditions. Seen from a distance on a mountainside, especially through a light fog, a patch of these plants looks decidedly like a congregation of several hundred priests. The vegetable sheep also are found in New Zealand, but there are no known intermediaries between the closely similar species growing on opposite sides of the earth. _The Octopus Worm: Evolution’s Mystery_ Worms that give birth to their own grandchildren, animals that have no digestive, muscular, nervous, glandular or excretory organs—such paradoxical creatures are the “dicyemid mosozoans”, tiny worms that live inside octopuses. These little worms are among the most curious living things in nature. It is quite uncertain whether they are a step upward in evolution from the single-celled protozoans or, like some other worms, a degenerate form of many-celled animals. It might be maintained that they represent a distinct branch of the animal kingdom. The body of a dicyemid consists of a single cell, almost half an inch long, in the form of a hollow tube, surrounded by a layer of small cells. The immediate offspring are formed and, in some cases, live their entire lives and reproduce in turn, inside one of these “skin” cells. The grandchildren break through the body of the grandparent at any place they choose, apparently without causing any wound, and live for a short time as free-swimming animals until they find an octopus whose kidneys they can enter. Then the whole life cycle starts over again.