Crustacea. 249 



basal joint bears one or two additional ones. Except this joint, all 

 possess long setae on the inner margin. 



The three posterior limits are of the walking type and also sul)- 

 similar. The basis, ischium, and meros are spinose on the outer 

 margin, and, particularly the first of these limbs, the meros to 

 propos inclusive bear numerous small spines on the inner margin. 



Pleopods. The first pair are coarse and spinose and form a case 

 protecting the remainder. These consist of a stout basis, spinose on 

 inner side and setose on the other. The exo- and endopodites are 

 large, somewhat widening distally, and having their margins richly 

 clothed with plumose setae. 



A large number of individuals were taken oft' Cape Adare during 

 November and December in from twenty to twenty-six fathoms. In 

 most cases the females had eggs or young in the brood pouch. One 

 fine specimen had no less than sixty young in its pouch. 



A small specimen was taken in 6 fathoms off Duke of York 

 Island and at a temperature of 28 • 75° Fahr, 



Arcturus adareanus.^ 

 (PI. XXXIIL, fig. 1.) 



Specific character. Body not spinose but minutely tuberculated. 

 Pleon segment uniformly covered with very small blunt spines and 

 terminating with two moderately long and parallel spines. 



This species is smaller and more slender than the last. The 

 spines, properly so-called, are confined to a pair on the cephalon, the 

 anterior thoracic segments, and the pleon. Spines are replaced by 

 small tubercles, which, however, take a spinous character in the 

 hinder part of the body. 



Cephalon. Anterior margin incurved : a pair of prominent blunt 

 spines arise between and somewhat in front of the large eyes. 

 Behind these is another pair of very much smaller spines. 



Thorax. The fourth segment is the largest and all are covered 

 with a number of small, closely-set tubercles : a pair of spines are 

 situated dorsally on the first segment. 



Pleon about as large as the four posterior thoracic segments. 

 The first three segments are distinct : these and the terminal shield 

 are covered with small spines. The extremity of this shield is 

 rounded and bears two prominent but blunt spines. 



The anatomical details bear a very close resemblance to the last 



^ Name altered, after author had sailed for the Antarctic. — F. J. B. 



