ENTOMOSTRACA. 
First Sub-Class. 
ENTOMOSTRACA 
299 
Order 1. Phyllopoda,—In these at least four pairs of leaf-like swimming 
feet bear respiratory plates. 
and is protected by a shield-like or bivalve shell. 
are without palps, and the maxille are rudimentary. 
(a) Branchiopoda. 
or more) foliaceous append- 
ages with respiratory plates. 
The shell is rarely absent, 
usually shield-like or bi- 
valved. The heart is a long 
dorsal vessel with numerous 
openings. The eggsare able 
to survive prolonged desicca- 
tion in the mud. 
Branchipus, a beautifully 
coloured _ fresh - water 
form, with hardly any 
shell. 
Artemia. Brine - shrimps. 
Periodically partheno- 
genetic. By gradually 
changing the salinity 
of the water, Schmanke- 
witsch was able, in the 
course of several gen-. 
erations, to modify 4. 
salina into A. mil- 
hauseniz, and vice versa. 
Artemia fertilts is one 
of the four animals 
known to occur in the 
dense waters of Salt 
Lake. 
Apus, an archaic fresh- 
water form with a large 
dorsal shield. 
The body is generally well segmented, 
The mandibles 
The body has numerous segments and (10-20. 
Fic. 153.—Dorsal surface of Apus 
cancriformts. —From  Bronn’s. 
Thierretch. 
In the anterior region are the two com- 
pound eyes, and behind them the 
simple unpaired eye. The whip-like 
outgrowths of the first thoracic ap- 
pendage project laterally. 
Afus is over an inch in length, a giant among Entomostraca. It has 
an almost world-wide distribution. 
numerous and mostly leaf-like. 
The appendages are very 
They may be regarded as. 
representing a primitive type of Crustacean limb. Professor 
Ray Lankester enumerates them as follows :— 
I. Antenna, 
Pre-oral. 2. Second antenna. 
Oral. 
4. Maxilla. 
3. Mandible. 
5. Maxillipede. 
(This is sometimes absent, and 
apparently always in certain species, ) 
