STALK-EYED CRUSTACEA 427 



I. Thaumastocheles. 



TJiauniastocJieles . Spence Bate, Wood-Mason. 

 Astaais Suhn. 



Carapace less than half the length of the animal, 

 dorsally flattened, divided by a moderately deep cervical 

 sulcus ; near the centre the lateral walls are depressed, 

 and the posterior margin is secured in its position by 

 a strong blunt process attached to the lateral portion 

 of the first joint of the abdomen. The abdomen is longer 

 than the carapace, and each segment increases in width 

 posteriorly to the fifth, then decreases. 



The eyes are absent or obsolete. 



Gills are attached to the body wall, to the membrane 

 between body and first joint of external maxillipede and 

 anterior four pair of legs, and to their first joint. There 

 are six branchial plates. 



I. Thaumastocheles zaleuca. 



Thaumastocheles zaleuca . Spence Bate, Wood-Mason. 

 Astaciis zaleucus . . . Suhn. 



Animal long and slender, sides subparallel and com- 

 pressed, dorsal surface smooth except on the antennal 

 and postocular regions of the carapace, on each side of 

 the rostrum, and the third and fourth segment of the 

 abdomen, where there are numerous short, thick tufts of 

 hair. Rostrum dorsally flat. The external antenna:^ are 

 about as long as the animal ; basal scale with serrated 

 edges. The first pair of legs asymmetrical. The right 

 being the larger, and furnished with slender, rod-like 

 fingers which are nearly as long as the animal ; their ex- 

 tremity is curved, and they are armed on their prehensile 



