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



Habitat.— Station 272, September 8, 1875; lat. 3° 48' S., long. 152° 56' E.; north 

 of the Low Archipelago ; depth, 2600 fathoms ; bottom, Radiolarian ooze ; bottom 

 temperature, 35°"1. One specimen. Trawled. 



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

 Archipelago; depth, 2350 fathoms; bottom, red clay; bottom temperature, 35 0- l. 

 Two specimens were taken; one a female 150 mm. (6 in.) in length, the other about 

 75 mm. (3 in.), apparently a female also. Trawled. 



The external tissue is thin, soft and submembranous in structure. 



Carapace furnished with a short, sharp-pointed rostrum, which is laterally compressed, 

 elevated above the orbit to a crest armed with three small teeth and one behind it ; 

 inferior margin ciliated. Dorsal carina lost at the cervical fossa, scarcely visible 

 over the gastric region, but reappears slightly over the cardiac. Cervical fossa 

 deep ; a slight groove divides the cardiac region into two portions, and the branchial 

 region is defined by a strong elevated ridge, which is lost anteriorly in the hepatic sulcus, 

 which is furnished with a short stout tooth. There is no distinct orbit, and no orbital 

 tooth, but there is a small antennal tooth, and a smaller one below it on the frontal margin. 



The pleon is dorsally smooth and even, but laterally compressed posterior to the third 

 somite. The fourth somite is carinated in the median hue and posteriorly projected in tbe 

 form of a small tooth ; and has the posterior margin more evenly crenated than shown 

 in the plate. The fifth somite is carinated in its entire length, and terminates in a 

 small sharp tooth ; the posterior margin of the somite is smooth and even. The sixth 

 somite is more distinctly crested, and terminates in a small tooth. 



The telson is long and pointed, dorsally flat, and has the sides compressed. 



The ophthalmus is borne on a moderately long, club-shaped, single-jointed ophthal- 

 mopod (PL LIV., a), which is curved, compressed, and fits into a hollow on the outer and 

 upper surface of the first joint of the first antenna. 



The first pair of antennas (b, b") has the first joint short, not longer than theophthal- 

 mopod, and armed on the outer margin with a short robust stylocerite, between the base 

 of which and the anterior margin is an oblique hollow in which the ophthalmopod is 

 lodged. The second and third joints are scarcely equal in length to the first ; the third 

 bears two long flagella, the extremities of which are broken, so that their length cannot 

 be determined. 



The second pair of antennoe (c) carries a large scaphocerite that extends to more than 

 twice the length of the peduncle of the first pair, and is armed with a sharp subapical 

 tooth on the outer side, and the second joint of the peduncle is furnished on the inner 

 distal angle with a strong ancecerite (c"). 



The mandibles (d) are large, and have a two-jointed synaphipod, the first joint of 

 which is large, broad, and foliaceous, and the second narrow, long, and subfoliaceous. The 



