ISOPODS OF NORTH AMERICA. 



335 



joints; the posterior thoracic appendages are smooth and devoid of 

 an}- such spines. 



"The uropoda are covered with numerous minute granulations but 

 bear no spines." BEDDARD." 



ARCTURUS CARIBB^EUS Richardson. 

 Arcturus caribbseus RICHARDSON, Proa U. S. Nat. Mus., XXIII, 1901, pp. 546-547. 



Locality. Near Aves Island, Caribbean Sea. 



Depth. 683 fathoms. 



Head with a deep excavation on the anterior margin, on either side of 

 which the antero- lateral margins are produced, each bearing a short 

 spine at the outer angle. Two long 

 spines are situated on the anterior 

 portion of the head, between the 

 eyes. The first pair of antennas, con- 

 sisting of four joints, reach two-thirds 

 of the length of the third joint of the 

 second pair of antennae. The first 

 joint of the second pair of antennas 

 is short and unarmed; the second joint 

 is armed with a small spine at the 

 base on the outer margin, and a large 

 spine on the upper lateral margin; the 

 third joint is about three times as 

 long as the second joint, and is armed 

 with two long spines at the upper 

 end; the fourth joint is about twice 

 as long as the third joint, and is armed 

 with a single spine at the upper end; 

 the fifth joint is somewhat longer 

 than the fourth and is unarmed; the 

 flagellum is long and consists of ten 

 joints. 



The first, second, third, and fifth 

 thoracic segments have each two long 

 projecting spines, one on either side 

 of the median dorsal line. The fourth, 

 sixth, and seventh segments are with- 

 out these spines. The first segment 

 has three spines, one large central spine and two small spines on each 

 antero-lateral margin. All the other thoracic segments have one long 

 spine on each lateral margin. 



"Challenger Report, XVII, 1886, pp. 112-113. 



FIG. 366. ARCTURUS CARIBB.EUS. 



