EGA, Dh 
lobe on its external base; the second joint is produced 
internally,.and the three terminal joints are short, the 
last being armed with several minute teeth; the outer 
pair of maxille are curved and slender, terminated by 
two denticulated pieces, and the inner pair of maxilla 
are still more slender, with several minute reflexed teeth 
at the tip.* The pleon is nearly as wide at the base as 
the terminal segment of the pereion; the four anterior 
segments are of equal size and short, with the lateral 
margins strongly produced posteriorly into an acute 
angle; the fifth segment is shorter than either of the 
preceding, whilst the terminal segment is large, flat, 
conical, or semiovate or semicircular, often with one or 
two central ridges ; each of the five basal segments bears 
on its underside two pairs of delicate membranous ciliated 
branchial plates, all of nearly equal size, and each pair 
arising from a transverse basal piece. ‘They do not cover 
the whole of the underside of the tail. The terminal 
segment also carries on each side a pair of flattened 
appendages that do not reach beyond the posterior 
extremity of the pleon. 
* Our description of the parts of the mouth is made from ga bicarinata. 
In Milne Edwards’s figures of details taken from ga emargiiata, the diffe- 
rent organs appear to be less denticulated at the tips. 
