56 
T. V. HODOSON. 
Notoxenus spinifer. 
(Plate IX., fig. 3.) 
Specific characters :— 
Cephalosome rounded, with long ocular peduncles ending in four small knobs surrounding the eye. 
Mesosome with mid-dorsal spine on each segment and also on first segment of metasome. 
Lateral extremities of every segment very distinct from each other. 
Urosome very nearly as long as six segments of the mesosome. Top-shaped, with diminutive 
preterminal uropoda. 
The body forms a pointed oval and is much vaulted anteriorly or round- 
shouldered. The interval between the third and fourth segments of the mesosome is a 
variable feature, but in no case is it specially conspicuous. 
The cephalosome is subcircular when seen from above, but at first sight it does 
not appear to be so owing to the foreshortening due to the curvature of the body. 
The eye-stalks arise laterally, they are slender and extremely long, nearly as long as 
the diameter of the cephalosome, and extend that structure beyond the first segment of 
the mesosome. They are slightly enlarged at the extremity, and the eye lies in the 
middle of four small, blunt lobes. 
The mesosome comprises seven distinct segments, in the first of which the 
cephalosome is to some extent embedded. The next three segments are straight, the 
third of the entire series being the widest. The three posterior segments are curved 
backwards, their curvature increasing as their diameter decreases. All the segments 
are provided with a backwardly curved spine in the mid-dorsal line, their size is 
proportionate to the size of the segment, but their position varies, those of the last three 
being on the posterior-border of their respective segments. The epimera are inseparable 
from their respective segments ; they are large and irregular in shape. Those of the 
first three segments are more or less directed forwards and to some extent rounded 
at the extremity, the fourth is more truncated, those of the last three are rounded. 
The metasome consists of a single segment, wedged in the curvature of the last 
segment of the mesosome, and the urosome; the former carries a mid-dorsal spine. 
The urosome is pointed, pegtop-shaped, more than one-third the length of the entire 
animal, with small preterminal uropoda. Its entire margin is fringed with small, 
rather coarse setrn, and its surface is also well covered. 
The uropoda are very small, single-jointed, with terminal setse. The entire body 
is rather sparsely covered with small setse; these are more abundant and conspicuous 
on the epimera. ? 
The first antenna has a peduncle of two joints, the basal one being quite twice 
as long as the other, both are setose distally ; the flagellum is about twice as long 
as the peduncle and has only four joints, the first being rather long. 
The second antenna has a peduncle of six joints ; of these the first two are very 
short, especially the second ; the third is as long as the two together ; the fourth is 
