lab 9 external crayfish

cephalothorax- body segment

the first segment of a crayfish, consisting of a head fused to the thorax.

abdomen- body segment

the multi-segmented posterior region of the crayfish used to swim backwards.

carapace

projects backwards from the head and covers all of the thorax. It has two functions; firstly it protects the gills, and secondly it provides a water channel that is a constant flow of oxygenated water to pass over the gills and enables the crayfish to breathe.

swimmerettes

help the crayfish swim, move water over the gills for respiration, and on the female they hold the larva (eggs).

cervical groove

separates the head and the thoracic regions.

abdomen segements

segements on abdomen

rostrum

located at the head section of the crayfish and protects the forward sensory equipment (eyestalks, antennules, antennae); helmet

appendages on head region

antennules

shorter antennae next to the long antennae, touch, taste, monitor equilibrium

antennae

the two long antennae protruding from the rostrum, feelers for touch and taste

madibles- mouth

bone-like 'kernels of corn' in the mouth covered by the maxillae, chew food

maxillae- mouth

hairy structures covering the mandibles that are like the maxillipeds but less 'leg-like', manipulate food and keep water moving over the gills

maxillipeds- mouth

hairy leg-like structures around the mouth, touch, taste and manipulate food

chelipeds

the two claws of the crayfish, defense and catching food

walking legs (four pairs)

main legs on the ventral side, movement, helps in respiration because they are attached to gills, so when it moves, it circulates water across its gills

base segment- sex of your specimen

female genital pore- sex of your specimen

located on the third pair of walking legs.

male sperm duct openings- sex of your specimen

located at the base of the fourth pair of walking legs.

uropods

appendages located on tail that are flat structures which help the cray fish swim

telson

the center paddle of the crayfish tail, kick flip