814 



THE VOYAGE OF H.M.S. CHALLENGER. 



specimens and the nearly allied species Nematocarcinus parvidentatiis were taken, differ in 

 having the rostrum somewhat shorter than in the more typical form, the apex scarcely 

 reaching beyond the distal extremity of the third joint of the peduncle of the first pair of 

 antennae; in this variation some approach is made to Nematocarcinus parvidentatiis. 



Nematocarcinus parvidentatiis, n. sp. (PI. CXXXII. fig. 7). 



Rostrum horizontal, less than half the length of the carapace, furnished with about 

 two and twenty small teeth and spinules, the spinules being most crowded over the dorsal 

 crest, and the teeth on the rostrum less closely planted. Lower margin unarmed and 

 fringed in its entire length with a row of thickly- set cilia. 



Ophthalmus rather smaller than in other species. 



Peduncle of the first pair of antennas subequal in length to the rostrum, and 

 supporting two flagella, very unequal in diameter. 



Telson subequal in length to the sixth pleopod, and furnished with a horizontal row 

 of several small spinules placed widely apart on the dorso-lateral angle. 



Habitat— Station 237, June 17, 1875; kit, 34° 37' N., long. 140° 32' E.; near 

 Yokohama, Japan; depth, 1875 fathoms; bottom, blue mud ; bottom temperature, 35° - 3. 

 Nine specimens; four males, five females. Associated with Nematocarcinus product us. 

 Trawled. 



The specimens are considerably damaged, none of the pereiopoda or antennas being- 

 preserved attached ; the rostrum is produced in a line horizontal with the dorsal surface 

 of the carapace, and is armed on the upper surface with about twenty-two spinules, of 

 which the anterior are only imperfectly transformed into teeth ; each little spinule has 

 a lobe posterior to it, with which it has an imperfect articulation. 



The upper margin is depressed anteriorly, whde the lower is straight, so that the apex 

 is formed by the upper surface descending to the lower, which gives it an arched 

 appearance ; the frontal margin has a well-developed antennal tooth, but the fronto-lateral 

 tooth appears to be entirely absent. 



The ophthalmus is rather smaller than usual and somewhat reniform in shape. 



The first pair of antenna? has the first joint of the peduncle deeply excavate, and 



