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



Pleon having the third somite elevated to a large tooth, and the fourth, fifth, and 

 sixth somites posteriorly produced to a small tooth. 

 Telson subequal in length with the sixth somite. 



Habitat— Station 194, September 29, 1874 ; lat. 4° 34' 0" S., long. 129° 57' 30" E.; 

 off Banda Island ; depth, 200 fathoms ; bottom, volcanic mud. Two specimens. 

 Dredged. 



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The rostrum is about half the length of the carapace and projects horizontally, with a 

 slight elevation towards the point ; the upper surface is armed at the base, rather anterior 

 to the frontal region, with six small teeth closely packed together, the rest being smooth ; 

 the lower margin is also smooth, excepting for the presence of two small teeth situated 

 near the middle. 



The pleon is dorsally carinated from the second to the sixth somite ; the third somite 

 is produced to a large tooth that overlaps the fourth for more than half its length ; the 

 fourth, fifth, and sixth somites are all produced posteriorly to a small tooth, the sixth 

 somite is longer than the fifth, and the telson is subequal with it. 



The ophthalmopoda (fig. 6a) are short, thick, and supported on a short and narrow 

 stalk, which enlarges a little from the base and is distally as broad as the ophthalmus ; 

 there is a small ocellus communicating freely with the ophthalmus. 



The first pair of antennte has the first joint deeply excavate to receive the ophthal- 

 mopod, the second and third joints are short, thick, and subcylindrical, and do not reach 

 beyond half the length of the rostrum ; the outer flagellum is large and about the 

 length of the carapace, the extremity being broken, the under surface is thickly fringed 

 with sensory hairs ; the inner and slender flagellum is missing. 



The second pair of gnathopoda and first pair of pereiopoda are robust, and the chela 

 of the latter short and thick. The rest of the pereiopoda are wanting, and the terminal 

 pair of pleopoda is longer than the telson. 



Observation. — The general aspect of the species is not unlike that of Acanthephyra 

 acanthitelsonis, the chief points of distinction being the different armature of the rostrum 

 and telson. 



