Glossary
Words used in the key and the group descriptions.
- Aperture diaphragm
- An adjustable opening under the stage that controls the cone of light reaching the specimen. Closing it increases contrast and depth of focus.
- Axopod
- A stiff, straight pseudopod with an internal core of microtubules, as in heliozoans.
- Bdelloid
- A rotifer group that creeps like a leech and can survive drying out. Common in moss.
- Carapace
- The shell-like covering of crustaceans such as water fleas.
- Chaetae
- Bristles on the segments of annelid worms.
- Chloroplast
- The green organelle where photosynthesis happens. Its shape (cup, ribbon, plates) helps identify algae.
- Cilia
- Short hair-like projections that beat together. Ciliates are covered in them; rotifers have them on the crown.
- Cirri
- Tufts of fused cilia used as little legs by hypotrich ciliates.
- Contractile vacuole
- A bubble that collects excess water in a cell and squeezes it out at regular intervals.
- Corona
- The ciliated crown at the front of a rotifer.
- Coverslip
- The thin square of glass laid over a drop of sample on a slide.
- Desmid
- A green alga built of two mirror halves joined at a waist.
- Dichotomous key
- An identification guide in which every step offers a choice between alternatives, leading step by step to a name. The key on this site often offers more than two choices per step.
- Eyespot
- A red pigment spot in many green flagellates that helps them sense the direction of light (also called stigma).
- Field number
- A number on the eyepiece, in millimetres, giving the diameter of the field diaphragm. Divided by the objective magnification, it gives the field of view at the slide.
- Flagellum
- A long whip-like projection used for swimming. Plural: flagella.
- Food vacuole
- A bubble inside a cell where swallowed food is digested.
- Frustule
- The glass shell of a diatom, made of two halves that fit like a box and lid.
- Lorica
- A protective case or shell secreted by some protists and rotifers.
- Macronucleus
- The large nucleus of a ciliate that runs the daily life of the cell; ciliates also have one or more small micronuclei.
- Mastax
- The muscular pharynx with hard jaws in rotifers. It pumps rhythmically while the animal feeds.
- Membranelles
- Rows of fused cilia that form a fringe around the mouth area of many ciliates.
- Metaboly
- The squirming change of shape seen in Euglena and its relatives.
- Nauplius
- The first larval stage of copepods and many other crustaceans.
- Peritrich
- A ciliate with a ring of cilia around a bell-shaped mouth end, such as Vorticella.
- Protist
- Any eukaryote that is not an animal, plant or fungus; most are single cells.
- Pseudopod
- A temporary extension of a cell used for moving and feeding, as in amoebae.
- Raphe
- A slit in the shell of some diatoms that lets them glide.
- Test
- The shell of a testate amoeba, either secreted or built from collected particles.
- Trichome
- A chain of cells forming a filament, as in cyanobacteria.
- Tun
- The dried, dormant state of a tardigrade.
- Wet mount
- A slide with a drop of living sample under a coverslip.
- Zooid
- One individual in a colony, for example one bell of a colonial peritrich.