Laguna @arine Laboratory 149 
Hyalella azteca (Sauss) 
(Figure 84) 
Body smooth, slightly compressed. Pleon segments one and two 
each produced into a small dorsal tooth. Side-plates one to four 
somewhat rectangular. Hyes nearly round. Antenna one, five to 
eight-jointed, flagellum longer than peduncle; joints of peduncle suc- 
cessively diminishing in length. Antenna two, slightly longer, the 
seven to ten-jointed flagellum longer than peduncle; joints of 
peduncle successively increasing in length. Maxillipeds, inner plate 
tipped with three short, stout spines, and edged on the inner side 
with slender compound sete; outer plate with nine toothed spines 
and very small palp. Maxilla two, both plates apically fringed with 
fine spinules, which, on the inner plate, are edged with two plumose 
sete. Mandible normal, principal and secondary plates dentate, 
plumose spinules in spine-row, molar large, with compound seta. 
Gnathopod one, small, slender, fourth joint with small pellucid 
boss on the distal hind end; fifth joint with bulging hind margin, 
fringed with row of spines and short teeth; sixth joint not so wide, 
but sub-equal in length, hind margin covered with fine, short hairs, 
curved finger reaching to end of the transverse, toothed palm. 
Gnathopod two in both male and female, with bulging fifth joint 
edged with spines, sixth joint in male very large and stout, longer 
than broad, oblique palm with two notches underneath the strong, 
curved finger. Finger not reaching to hinder margin of palm, but 
closing between two spines just in front of a third notch. Gnath- 
opod two in female, longer and stronger than gnathopod one, fifth 
joint considerably produced behind, sixth joint twice as long as 
widest part; hind part produced somewhat beyond the small curved 
finger and the convex, transverse palm. Pereopods three to five, 
second joint broadly expanded, serrate; pereeopods four and _ five 
nearly equal in length. Pleopods plumose. Uropod three, ramus 
slender, tipped with sete, and subequal to peduncle. 'Telson, broad 
as long; rounded apical margin with slender seta on either side of 
tip. 
Specimens agreeing well with description of H. azteca in Das 
Tierreich, except in being smaller, and in having, commonly, fewer 
joints in the antenne. They differ from the family description of 
Talitridae in having the inner plate of maxilla one tipped with three 
plumose sete, and in having the fine spinules of the inner plate of 
maxilla two edged with two plumose sete. 
Color varying from light bluish green to light green and brown. 
Frequent in fresh water pond about five miles inland from 
Laguna Beach, California. Coll. H. V. M. Hall. 
