312 THE VOYAGE OF H.M.S. CHALLENGER. 



Aristeus armatus, Spence Bate (Pis. XLV., XLVL). 



Ar intern armatus, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol. viii. p. 188, 1881. 



Rostrum as long as the carapace, slender, slightly curved upwards, armed with three 

 sharp teeth at the base; dorsal surface smooth, without any carina, anterior margin armed 

 with two antennal teeth, the orbital tooth suppressed. A short longitudinal rib defines 

 the branchial region, which is covered by soft and flexible tissue. The pleon is dorsally 

 armed with three sharp teeth, situated on the third, fourth, and fifth somites, and there is 

 a low carina on the sixth. 



Telson narrow, tapering, dorsally flattened and laterally compressed ; fringed with 

 hairs and bearing four small spines near the distal extremity. 



The ophthalmopoda are club-shaped and rigid. 



The first pair of antennas carries a stylocerite that reaches to the extremity of the 

 second joint, and the third joint carries a very short and flat flagellum, and a second 

 long and slender, being cpiite as long as the whole animal. 



The female corresponds very closely with the male, except in having a greater width 

 between the posterior pereiopoda, and in having the ventral plate broader and flatter. 



Habitat— Station 133, October 11, 1873; lat. 35° 41' S., long. 20° 55' W.; South 

 Atlantic Ocean, near Tristan da Cunha ; depth, 1900 fathoms ; bottom, Globigerina ooze ; 

 bottom temperature, 35 0, 4. One specimen. Trawled. 



Length (male), 150 mm. (6 in.), measured from the orbit to the extremity of the 

 telson. 



Station 184, August 29, 1874; lat. 12° / 8' S., long. 145° 10' E.; near Torres Strait; 

 depth, 1400 fathoms; bottom, Globigerina ooze; bottom temperature, 36°. One female 

 and two males. Trawled. 



Length — male, 200 mm. (8 in.); female, about 12 mm. shorter. 



Station 213, February 8, 1875 ; lat. 5° 47' N., long. 124° 1' E.; near the Philippines ; 

 depth, 2050 fathoms ; bottom, blue mud ; bottom temperature, 38°"8. One specimen. 

 Trawled. 



Length (male), 70 mm. (275 in.). 



Station 237, June 17, 1875 ; lat. 34° 37' N., long. 140° 32'E.; off Japan; depth, 1875 

 fathoms; bottom, blue mud ; bottom temperature, 3 5° "3. One female. Trawled. 



Station 246, July 2, 1875; lat. 36° 10' N., long. 178° 0' E.; Mid-Pacific; depth, 

 2050 fathoms; bottom, Globigerina ooze; bottom temperature, 35°"1. One specimen. 

 Trawled. 



Length (male), 177 mm. (7 in.). 



Station 276, September 16, 1875; lat. 13° 28' S., long. 149° 30' W.; the Low 

 Archipelago; depth, 2350 fathoms; bottom, red clay; bottom temperature, 35° - l. One 

 specimen ; female. 



