CHAPTER VI
WORMS
Suggestions:—Earthworms may be found in the daytime after a heavy rain, or by digging or turning over planks, logs, etc., in damp places. They may be found on the surface at night by searching with a lantern. Live specimens may be kept in the laboratory in a box packed with damp (not wet) loam and dead leaves. They may be fed on bits of fat meat, cabbage, onion, etc., dropped on the surface. When studying live worms, they should be allowed to crawl on damp paper or wood. An earthworm placed in a glass tube with rich, damp soil, may be watched from day to day.
External Features.—Is the body bilateral? Is there a
dorsal and ventral surface? Can you show this by a test
with live worm? Do you know of an animal with dorsal
and ventral surface, but not
bilateral?
 | An image should appear at this position in the text. To use the entire page scan as a placeholder, edit this page and replace "{{missing image}}" with "{{raw image|First course in biology (IA firstcourseinbio00bailrich).pdf/278}}". Otherwise, if you are able to provide the image then please do so. For guidance, see Wikisource:Image guidelines and Help:Adding images. |  |
Fig. 69.—An Earthworm.
Can you make out a head? A head end? A neck? Touch the head and test whether itcan be made to crawl backwards. Which end is more tapering? Is the mouth at the tip of the head end or on the upper or lower surface? How is the vent situated? Its shape? As the worm lies on a horizontal surface, is the body anywhere flattened? Are there any very distinct divisions in the body? Do you see any eyes?
Experiment to find whether the worm is sensitive (1) to touch,
(2) to light, (3) to strong odors, (4) to irritating liquids. Does it
show a sense of taste? The experiments should show whether
