Keith Forman, age 10, of Staten Island, New York, for his question:

What is a coelacanth?

The spelling of his name does not give you much help in pronouncing it. You say it as if it were spelled see luh kanth. Until you master the spelling and the pronun¬ciation, it is quite all right to refer to the coelacanth as a living fossil. Scientists thought that he left the world ages ago and then found he is still living.

We have found in the ground the fossil remains of many animal species that died out in the dim past. If we found a real live dinosaur browsing in some remote swamp, the whole world would be astounded. The dinosaurs and all their kinfolk said "Goodbye" to the world about 60 million years ago and departed forever. We can be sure of this. Scientists also thought that they could be sure that the coelacanth also departed at about the same time. Many fossil coelacanths were found in the dregs of muddy sea beds, but the huge, odd shaped fish seemed to belong in the distant past. Certainly he re¬sembled none of the living fishes and the coelacanth was classified as extinct, with the dinosaurs.

Fossil evidence suggests that the first backboned animals appeared about 400 million years ago. They were smallish, armor coated fishes with no teeth or jaws and none of them survived to modern times. The bony fishes appeared about 300 million years ago and their descendants include the silvery mackerel, the flat sole and the streamlined tuna. One of the early fishes had stubby limbs with stiff fins at the end of them. Scientists called his stubby limbs lobes and classified him as a lobe finned fish    alias the coelacanth. His descendants improved their stubby lobes, swapped them for real limbs and became amphibians. Everyone assumed that none of the fishy ancestors survived.

Then in 1938 a boat was fishing in deep water off the coast of Africa, and the nets dredged up an extraordinary large blue fish. Of all things, his fins were fixed at the ends of stubby limbs. The fishermen took him ashore to be identified by experts. Most of his oily body decayed on the way, but there was enough of him left to say for sure that he was a coelacanth. The world of science had to update a classification. The coelacanth fish species, labeled extinct, was transferred to the land of the living. Fishermen and marine biologists went dredging for more specimens. Two more big blue coelacanths were hauled up from the deep. This time they were handled with care. Their bones and internal organs were studied in detail and their big blue bodies were stuffed and preserved.

The fossilized remains of past animals date back and back through some 500 million years and the story of life on earth began in the ancient seas. The descendants of the early creatures improved themselves. Most of the early species perished and newer, improved species survived. The coelacanth is an ancient model who survived  ¬a living fossil. The watery cradle of life still holds many secrets, and most likely our probing sea labs will discover other unknown creatures living down in the midnight darkness of the deep ocean.