Annelids and Arthropods Lab

Annelids and Arthropods

What is an Annelid?

An Annelid is defined as a segmented worm in the Annalida phylum.

The Annalida phylum defining characteristics

  1. Symmetry and Size
  2. Coelom
  3. Body Wall
  4. Parapodia
  5. Nervous system
  6. Sense Organs
  7. Circulation and respiratory structures
  8. Segmental organs

Neris worm

Nexis worms in perservative
Nereis worm head
Image produced by myself

What is the primary way of feeding for these segmented worms?

They primarily feed on decomposed plants materials and this applies all of the species of segmented worms except leeches (freshwater segmented worm) that feed on blood.

Where are Neres Worms Typically found?

The Neres Worm or rag worm are common North American species is Nereis limnicolafound on the Atlantic and Pacific coasts. N. virens, which may be as long as 80 cm (31.5 inches), occurs on both sides of the North Atlantic.

Nereis parapodia

Image from Wikipedia

Differences between Errant and Sedentary polychaetes

Errant Polychaetes
Image from Wiki
Sedentary Polychaetes
Image from Wiki


  1. Body Segments – A large number

2. Anterior appendages –

Few in number and differentiated into palps, antennae, tentacular cirri, etc

3. Life Habit – Free living and generally rapacious

4. Feeding: (breast mode) all have jaws; scavengers or predators (on plants and animals)

Learn more from the source :


  1. Body Segments – A limited number ; May be separated into different segments

2. Anterior appendages

May be absent or a few to many similar appendages

3. Life habit – Tubicolous or burrowing

4. Feeding: (animalistic) usually  filter- or deposit-feeders (i.e. consume sediment)


Main Characteristics of Arthropods

All arthropods share a common set of characteristics that include having jointed limbs, an exoskeleton, good senses, and bilateral body symmetry. An exoskeleton is a hard, shell-like covering that protects an arthropod’s inside body parts.


Crayfish 4 alternating size images from myself an example of an arthropod
2 Crayfish in presevatives an example of two large crayfish classified as an arthropod

Observing other Arthropods


This is an image of another crab .
Both images were captured by myself.
Image 1 and 2 were taken by myself and are hermit crabs
The hermit crab species is a Caribbean hermit crab and is indigoes to the Caribbean

Horse Shoe Crab

Dried up raisin looking Horseshoe Crab
Horseshoe in preserves in a container

What does the animal use for respiration?

Book gills are used for both swimming and breathing. They are covered in a membrane that allows oxygen to enter but repels water. … The operculum covers and protects the other five pairs of gills. 

A horseshoe crab is not a crab- how does it differ from the “real” crabs?

Horseshoe crabs are “living fossils” more closely related to spiders and scorpions than they are to crabs.

What are the barnacle shells ?

How does this animal feed?

Barnacles feed through feather-like appendages called cirri. As the cirri rapidly extend and retract through the opening at the top of the barnacle, they comb the water for microscopic organisms. … Four more plates form a “door” that the barnacle can open or close, depending on the tide.

Locate and watch a video of barnacles feeding on youtube……

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