414 THE VOYAGE OF H.M.S. CHALLENGEE. 



" First pair of antennae having the peduncle two-thirds the length of the carapace, and 

 about the fifth part of the length of the animal (or a little longer) ; third joint longer than 

 the first, distinctly clavate, and much longer than the second. 



" Second pair of antennae having the last joint of the peduncle linear, equalling half 

 the length of the narrow scaphocerite. 



" Sixth somite of the pleon exceeding a little the sixth part of the length of the 

 animal, and nearly twice as long as broad, and one-fifth longer than the telson. 



" Pleopoda long and slender. 



" Rhipidura having the external margin armed with a sharp tooth, about one-third 

 from the apex. 



"Length, 4 mm. (0-16 in.)." 



Rostrum horizontally continuous with the dorsal surface of the carapace. 



Pleon having the five anterior somites subequal, the fourth and fifth being armed 

 with a strong dorsal tooth, a rudiment of another tooth apparently existing on the third 

 also. The sixth somite is about as long as the two preceding, and projects posteriorly at 

 the dorsal margin into a small tooth. 



The telson reaches to rather more than half the length of the rhipidura. 



The ophthalmopod reaches beyond the extremity of the second joint of the peduncle 

 of the first pair of antennas. The ophthalnxus is ovate and implanted obliquely on the 

 stalk ; the inner or extended portion is continuous with the inner or upper margin of the 

 stalk, which causes the latter to appear arched. 



The first pair of antennas is imperfect, being broken off at the extremity of the 

 peduncle. The second pair is also broken, but the scaphocerite is present and reaches to 

 about two-thirds the length of the peduncle of the upper antennas ; it is narrow, with 

 the margins almost parallel, fringed with cilia at the inner margin, and armed with a 

 tooth at the outer angle of the apex. 



The first pair of gnathopoda is generic in character. The second pair is long and 

 powerful, but the terminal joint is slender and fringed with cilia. 



The first pair of pereiopoda is about two-thirds the length of the others, which are a 

 little less in length than the second pair of gnathopoda, feeble in character and fringed 

 with hairs. The last two are rudimentary. 



The pleopoda are slender but not extremely long, the fifth pair being the shortest 

 and most robust. The sixth or ultimate pair, which forms the lateral portion of the 

 rhipidura, is armed on the outer margin of the external plate with a feeble hair-like 

 tooth, situated rather more than a third from the apex, beyond which the margin is 

 furnished with hairs fringed with cilia. 



Length, 7 mm. (0'3 in.). 



Habitat. — New Hebrides; Pacific, July 20, 1875; Greenland (Kroyer). 



