Worm Lab
Purpose: To use compound microscopes to identify
the anatomy of the clam (sand) worm, Nereis.
Materials: Compound Microscope, Prepared Slides
of Nereis:
1. Nereis – Draw in Plain View
2. Nereis Parapodium - label parapodia &
setae
1. Dorsal cirrus
2. Notopodium
3. Setae
4. Neuropodium
5. Ventral cirrus
6. Acicula
This slide shows a parapodium from a polychaete worm.This biramous appendage
consists of a ventral division called the neuropodium and a dorsal division called
the notopodium, each of which is supported by a stiff chitinous rod called an
aciculum. A dorsal cirrus and ventral cirrus (richly supplied with sensory
receptors) project from the notopodium and the neuropodium respectively.
Numerous dark staining setae that extend beyond the parapodium can also be
seen on this slide.
3. Dipylidium canium Scolex
4. Fasciolia hepatica - liver fluke
5. Planarian
6. Ascaris lumbricoides male
1. Cuticle and hypodermis
2. Longitudinal muscle layer
3. Vas deferens
4. Testis
5. Lateral line with excretory canal
6. Intestine
7.Pseudocoelom
This slide shows a cross section of a stained, male, large intestinal roundworm
(Ascaris lumbricoides). This nematode is a common parasite of humans, with
over a billion people infected worldwide. The section shows the outer
protective cuticle secreted by the underlying hypodermis. Longitudinal
muscle bands, dorsal and ventral nerve cords, lateral lines (containing the
excretory canals), the intestine and pseudocoelom (body cavity) are also
visible. The slide also contain various sections through the long, coiled testis
and vas deferens, the latter of which contains the ameboid spermatocytes
(sperm cells). Note: These structures may differ in shape, depending on the
way they were sectioned.
7. Trichinella spiralis encysted larvae
1. Encysted larvae
2. Skeletal muscle
fibers
This slide shows a section of skeletal muscle the containing encysted larvae of the
nematode parasite Trichinella spiralis. Humans can contract the parasite by eating
raw or inadequately cooked pork or bear meat. Once ingested, enzymes in the
digestive system trigger the release of the encysted worms, which mature, mate and
produce offspring. These juvenile worms then enter the host's lymphatic system
and are distributed through the body via the circulatory system to active skeletal
muscle into which they burrow and become enclosed in cysts.
8. Tapeworm proglottids comparison
Methods:
1. Use compound microscope to identify and sketch
prepared specimens
2. Note the total magnification for each drawing
3. Label the parapodium & setae for the 2nd slide.
Figure 1. Dorsal view of the head of Nereis virens. Poly76La.gif