48 Benedict — Arduridse in the U. S. National Museum. 



spines on the joints of the anterior series of ambulatory legs, and by the 

 outline of the abdomen. Length of the largest specimen 23 mm. 



Station 2756, off Cape St. Roque, Brazil, hit. 3° 22' 00" S., long. 37° 

 49' 00" W., 417 fathoms; two males (No. 21252, U. S. N. M.). 



Aicturus americanus Beddard. 



Arcturus americanus Beddard, Report on the Isopoda collected by the 

 'Challenger,' p. 104, pi. xxiii, tigs. 5-8, L886. 



Color of specimens in alcohol : Body light straw color; the head is 

 shaded with purple ; this shade continues in two broken lines to the sixth 

 segment, where the lines are united, spreading again on the abdomen. 

 Another broken line runs along the second, third, and fourth segments 

 at a little distance above the epimera ; on the posterior segments the line 

 is continued close to the epimera. There are two purple rings on the 

 third joint of the antennas and a broad hand near the distal ends of the 

 fourth and fifth joints. 



Specimens were obtained at two stations off the east coast of Patagonia : 

 Station 2768, lat, 42° 24 / 00" S., long. 61° 38' 30" W., 43 fathoms; 

 Station 2770, lat. 48° 37' 00" S., long. 65° 41/ 00" W., 58 fathoms ; four 

 specimens. 



Aicturus multispinis sp. nov. 



The head is a little elongated ; the front is concave. The eyes are round 



and stand out from the sides of the 

 head as hemispheres. Two spines 

 are placed near the front in advance 

 of the line of the eyes and a trans- 

 verse line of six a little behind the 

 eyes ; the terminal spines of the row 

 are much smaller than the others. 



The antennae are 2S mm. in length 

 and slender in comparison with 

 those of the Arctic forms ; there are 

 two spines on the second segment 

 and two on the third segment of one, 

 and three on the other; the fourth 

 segment is armed with .a single spine 

 at its articulation with the fifth seg- 

 ment ; the fifth segment is consid- 

 erably longer than the fourth; the 

 flagellum is short and without joints. 



The two spines near the front form 

 the anterior ends of two rows that 

 extend to the last segment of the 

 abdomen; the first four segments 

 of the thorax have a transverse con- 

 striction making them in appearance 

 double segments ; both the anterior 

 Fig. 8.— Arcturus multispinis. (X 2%.) and posterior portions of these seg- 

 ments furnish a pair of spines for the lateral dorsal lines of spines ; after 



