50 STALK-EYED CRUSTACEA 



Rostrum small, scarcely longer than wide, and is formed 

 of two flat horns, pointed and diverging, of which the 

 base occupies almost the whole width of the front. 



The eyes are large. The orbits are oval and directed 

 obliquely forwards, outwards, and upwards ; their superior 

 border presents two small fissures, through which the 

 retracted eyes are visible, and terminates anteriorly in a 

 small spine, less projecting than the spine situated below 

 it, which belongs to the basal joint of the external 

 antennas ; the inferior border is complete and has no 

 fissure. 



The arrangement of the antennary region, of the 

 external antennas, of the external maxillipedes, of the 

 sternal plastron, and of the legs, is essentially the same as 

 in the genus Pisa. 



The abdomen is seven-jointed. 



Range. — The Mediterranean Sea, Tropical Atlantic, 

 West Coast of Mexico, Australia ; at moderate depths. 



I, Herbstia depressa. 



Herbstia depressa . A. Milne Edwards, Stimpson. 

 Herbstiella depressa . Stimpson. 



Carapace generally covered with sordes adhering to 

 a slight pubescence easily detached, beneath which the 

 surface is glabrous and slightly tuberculose. There is 

 a median protuberance on the gastric, and one on the 

 cardiac region ; two tubercles on the intestinal region in 

 a transverse row. Lateral and posterior margin armed 

 with small spiniform tubercles. A stout spine on the 

 hepatic region. 



Rostrum with the horns triangular. Frontal region 

 and the surface of the rostrum with a median longitudinal 

 sulcus between two short prominent ridges. 



