LETTERS: A QUICK ZOOLOGY LESSON

To the editor:

On the local TV news broadcast recently, the reporter was describing how embryonic cloning may someday be of medical benefit. At one point she demonstrated by snipping an adult Lumbricus terrestris (an earthworm) into exact halves and explained that each would then grow into two complete new worms.

Whoa! According to what my zoology book explained, an earthworm is a very complex animal. With a tubular body made of some 150 to 180 segments, it has a distinct head end with a mouth, a brain in segment 3, 10 hearts in segments 5 through 10, a crop, gizzard and stomach extending back to segment 35 (not quite halfway and then a complete intestine extending to the posterior end.

If cut into halves around segment 100, the head end probably would live, but the tail end would not.

To all my former students in L.J. Schultz science classes, where we dissected thousands of specimens, the earthworm anatomy has not evolved to where if cut in halves each would grow into a new worm. It hasn't changed.

ELROY "ROY" KINDER, Retired science teacher

Cape Girardeau