Crayfish Dissection Lab Companion

You will be responsible for identifying the following items on a crayfish specimen:

• cephalothorax

• abdomen

• antenna

• antennule

• swimmerets

• walking legs

• cheliped

• rostrum

• mandible

• cervical groove

• uropod

• telson

• anus

• stalked eye

• carapace

• dorsal suture

• dactylopodite

• propodite

• carpopodite

• cardiac stomach

• digestive gland

• gastric mill

• gills

• heart

• intestine

• ventral nerve cord

You will be responsible for answering the following types of questions concerning the crayfish:

• Explain how to distinguish between male and female crayfish.

• What does the term "in berry" refer to when discussing crayfish?

• What is the "gastric mill" and where in the crayfish is this structure located?

• The order the crayfish belongs to is called "Decapoda".  The prefix "deca" means ten, and the suffix "poda" means leg.  Why is this a good name for the crayfish?

• What are the abdominal somites?

• Be able to identify the crayfish phylogeny.  (see table below)

• What type of substance is chitin?  What is the purpose of chitin (for the crayfish)?

• Why must the crayfish occasionally molt?

Crayfish Phylogeny:

Below are a few diagrams which will help you identify items on your crayfish during your lab experience: