284 
PHYLUM. ARTHROPODA. 
THE APPENDAGES OF THE CRAYFISH 
Head 
(s) 
Thorax 
(8). 
Abdomen 
(6). 
No. 
™ 
NAME. 
FuncTION, 
STRUCTURE. 
Antennules (pre- 
oral ?). 
Antenne 
oral ?). 
Mandibles. 
(pre- 
ust Maxillee. 
and Maxille. 
Tactile, olfactory, 
with ear-sac at 
base. 
Tactile, opening of 
kidney at base. 
Masticatory. 
i 
Produces respira- 
tory current. 
Two branches, but probably 
not homologous with endo- 
podite and exopodite. 
Small exopodite. 
Four joints, of which three 
form the palp (endopodite 
and upper joint of proto- 
podite). 
Thin single-jointed protopo- 
dite, small endopodite, no 
exopodite. 
Thin protopodite, filamen- 
tous endopodite; the 
“baler” is formed from 
the epipodite, probably 
along with the exopodite. 
ist Maxillipedes 
(foot-jaws). 
Walking Legs 
(chelate). 
2nd Maxillipedes. 
3rd Maxillipedes. 
Forceps (chelate). 
Masticatory. 
Fighting, seizing. 
Walking. 
Genital opening in 
female. 
Genital opening in 
male, 
Thin protopodite, small en- 
dopodite, large exopodite. 
Two- jointed protopodite, 
five - jointed endopodite, 
long exopodite. 
Two - jointed protopodite, | 
large five-jointed eidopo- 
dite with strong teeth on 
its ischiopodite, slender 
exopodite. 
No exopodite. In the claw 
the last joint bites against 
a prolongation of the 
second last. 
Without chela. 
” 
Modified swim- 
merets in male; 
in female, rudi- 
mentary, 
Modified swim- 
merets in male, 
Swimmerets. 
” 
. 
Great paddles. 
normal in female. 
Serve in the male 
as canals for the 
seminal fluid. 
oars, and carry 
the eggs in the 
female. 
Important in swim- 
ming. 
ee slightly like 
[Protopodite and endopodite 
form acanal; no exopodite. 
All the three parts, 
