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



terminal ; near the centre of the former stands a large petasma, beyond which, on the 

 same surface, is a small projecting calcareous process. The second pair of pleopoda 

 differs from the first in being biramose, the inner branch being short and robust, lobed 

 at the base, obtusely pointed and anteriorly obliquely truncate. The third pair of 

 pleopoda is shorter than the preceding, the two rami are similar in character, but the 

 inner branch is somewhat stouter at the base than the outer. The fourth pair of 

 pleopoda is shorter than the third, and the fifth is shorter than the fourth. 



The posterior pair, which forms the outer branches of the rhipidura, has a short 

 basal joint and two long foliaceous branches, the inner of which is fringed with long 

 hairs and is twice the length of the telson, while the outer is about one-fourth longer 

 than the inner and furnished with a small tooth near the distal extremity of the outer 

 margin, the inner margin being fringed with long hairs. 



Length, 9 mm. (0-36 in.). 



Female. — In general aspect the female bears a close resemblance to the male, and 

 even the differences other than sexual, which I have been able to determine, are such as 

 may not be constant in all specimens. The one under examination is a little larger 

 than the male ; it has the ophthalmopoda relatively a little shorter, and the phymacerite 

 slightly longer. It has the first pair of pereiopoda shorter than the second pair of 

 gnathopoda. The pointed processes on the lateral margins, at the base of the pleopoda, 

 are larger and more conspicuous than in the male. The sixth somite has the lateral 

 margins furnished with a single tooth, and that a very small one, one-third of the 

 length distant from the posterior extremity. The pleopoda are generally longer and 

 more slender ; the first pair is single-branched and free from the secondary sexual 

 appendage ; the second and following pairs are biramose and slender ; the terminal pair 

 resembles that of the male. The telson is free from the inferior lobe, terminates in 

 two small spines, and is flanked on each side by another still smaller. 



Length, 10 mm. (0"4 in.). 



Habitat.— Arafura Sea; near Station 270, Mid-Pacific, lat. 2° 34' N., long. 149° 9' 

 W. ; Philippine Islands ; Port Jackson (female) ; off Samboangan ; West Pacific ; Mid- 

 Pacific ; St. Paul's Eocks ; Tropical part of Atlantic ; North Atlantic. 



Lucifer reynaudii, Milne-Edwards (PI. LXXXIV.). 



Leucifer reynaudii, Milne-Edwards, Hist. Nat. Crust., t. ii. p. 469. 



Male. — Cephalon anteriorly produced in advance of the epistoma to about one-fifth 

 of the length of the animal ; dorsal surface produced to a sharp rostrum ; a prominent 

 tooth is produced on each side at the inferior antennal angle. The pereion is about 

 one-third shorter than the cephalon ; it is deeper posteriorly than anteriorly, and 



