STALK-EYED CRUSTACEA 75 



Abdomen is seven-jointed. 



Range. — Warm parts of the Atlantic and Pacific 

 Oceans ; in shallow and deep water. 



Synopsis of the Species. 



A. Lateral epibranchial spine well developed. 



a. Tooth on the antero-external angle of basal joint 

 of external antenna; prominent. 



a^. One median spine, directed backwards, between 

 the epibranchial spines. — {A/, trispinosa.) 



b^. A row of spines across the back, directed back- 

 wards, between the epibranchial spines. — (J/, subparallcla.) 



b. Tooth on the antero-external angle of basal joint 

 of external antenna; not prominent. 



d. No spines on back between the epibranchial spines. 

 —{M. diplacantka.) 



B. Lateral epibranchial spine small or none. 



c. /\ntenn3e longer than rostrum. 



d^. One spine only, on intestinal region. — (J/, lavigaia.) 



A. Lateral epibranchial spine zvell developed : — 



I, Macrocoeloma trispinosa. 



J\Iacroca:loina trispinosa . . Latreille, Miers. 



Pericera nudipes .... Desbonne and Schramm. 



Periccra trispinosa . . . H. Milne Edwards. 



Pisa trispinosa Latreille. 



The posterior portion of the carapace is triangular, 

 and armed with three strong spines, two lateral and one 

 median, directed backwards ; surface embossed ; the front 

 is larce. The anterior and external anijle of the orbit is 



