CYMODOCEA. 4.25 
ISOPODA. SPH AROMID A, 
NORMALIA. 
Genus—CYMODOCEA.  (Leach.) 
Generic character. Not capable of being completely rolled 
intoa ball. Pleon very rugose, deeply excavated at the tip, 
with a lobe or tooth in the middle. Uropoda with the plates 
elevated obliquely, so as not to shut under each other, the 
inner plate being a process of the peduncle. 
THESE species are easily distinguished by the very 
rugose and setose segments of the tail, which is terminated 
by a deep notch, within which is a produced central plate 
or lobe. The body is more parallel at the sides than in 
Spheroma, all the segments being simple. These charac- 
ters will at once distinguish the genus both from Spheroma 
and Dynamene, which latter has been united with it as a 
second section by Professor Milne Edwards. 
The head is nearly as broad as the broadest part of the 
body. ‘The flagella of both pairs of antennz are multi- 
articulate. The penultimate segment of the tail (forming 
the posterior margin of the consolidated basal mass) is 
prolonged in the middle and emarginate, the terminal 
segment bearing in the centre of its upper surface a com- 
pound tooth or spine, and the extremity of the tail is 
deeply notched, with a short horn or lobe in the middle 
of the notch. The foot-jaws have the intermediate joints 
prolonged on the inner margin, the extremity of the lobes 
thus formed being thickly ciliated. The lateral appen- 
dages of the tail have two small lobes, which are strongly 
ciliated with stiff short hairs, which also are thickly 
scattered upon the upper surface of the segments of the 
tail. 
