GAMMARIDES. 
235 
A MP HIP OP A . a A MM A RIDES. 
NATATORIA. 
Subfamily — GAMMARIDES. 
Body compressed. Eyes two, situated on a lobe between the 
superior and inferior antennae. Inferior antennae not situated 
posteriorly to the superior. Posterior pair of pleopoda folia- 
ceous. 
The animals constituting this subfamily are generally 
much compressed laterally. They have two eyes, which 
are situated on a lobe of the walls of the head, which 
project anteriorly between the superior and inferior 
antennae. The antennae are planted one above the other, 
and are generally long, slender, and terminate in a fila- 
mentary flagellum. The first two pairs of arms are 
subchelate, and generally well developed. The posterior 
pair of caudal appendages are generally leaf-like, and 
fringed with cilia or hairs, but never stout spines or 
hooks. The terminal tail-piece is generally squamifonn, 
except in one or two genera, where it appears to be 
tubular or cylindrical, resembling a rudimentary seg- 
ment. 
This subfamily must be considered as containing the 
normal types of the order, the others being greater or 
less departures from this perfect form. They are in- 
variably aquatic animals, existing in fresh as well as 
sea water ; and are most numerously distributed on our 
shores. 
