152 
THE VOYAGE OF H.M.S. CHALLENGER. 
The single specimen (which is a female, perhaps not fully adult), was obtained near 
Bahia, in 7 to 20 fathoms, with Pilumnus fioridanus. 
This species evidently belongs to the same section of the genus as Pilumnus aculeatus 
(Say), Pilumnus vinaceus, A. Milne Edwards, and Pilumnus caribaeus, Desbonne. It is 
more nearly allied to the last-mentioned species than to any other of the genus with 
which I am acquainted, agreeing with it and differing from other allied American species 
(as described by authors) in having the outer surface of the palms of both chelipedes 
wholly covered with strong, longitudinally seriate, spiniform tubercles, but it differs in the 
smooth (not granulated or spinuliferous) carapace, and in the absence of a pterygostomian 
spine. 
From Pilumnus gracilipes, A. Milne Edwards, it is apparently distinguished by the 
well-developed spinules of the upper orbital margin and by the absence of tubercles or 
spines from the subhepatic and pterygostomian regions. 1 
Pilumnus fioridanus, Stimpson (PL XIII. fig. 3). 
Pilumnus fioridanus, Stimpson, Bull. Mus. Comp. Zool., vol. ii. p. 141, 1870. 
„ ,, A. Milne Edwards, Crust, in Miss. Sci. au Mexique, pt. 5, p. 287, 1880. 
Here is referred an adult ova-bearing female, dredged off the coast of Brazil, in from 
30 to 350 fathoms, lat. 9° 5' 0" S. to 9° 10' 0" S., long. 34° 49' 0" W. to 34° 53' 0" W. 
(Stations 122-1 22c). 
This specimen scarcely differs from Stimpson’s description in any particular, except 
in the absence of a transverse series of longer hairs on the frontal region. Several such 
hairs exist, however, near the front and antero-lateral margins. 
From Pilumnus quoyi, Milne Edwards, found at Bio de Janeiro, 2 this species 
would seem to be distinguished by the spinose ambulatory legs. 
Three males collected near Bahia, in shallow water, are also doubtfully referred to 
this species. They are distinguished from the typical Pilumnus fioridanus only by the 
absence of the tubercles from that part of the outer surface of the palm of the larger 
chelipede which lies nearest to the base of the lower (immobile) finger. In all other 
particulars, as ( e.g .) the non-spinuliferous lobes of the front and upper margins of the orhits, 
the form of the carapace, and the moderately robust and elongated spinuliferous and 
hairy ambulatory legs, they agree with the typical form of the species. In one (the 
smallest) of these specimens, the tubercles cover a larger part of the outer surface of the 
palm than in the others. It is worthy of note that the type of Stimpson’s description 
was a female ; I think it therefore possible, that the partial absence of the tubercles of 
the palm of the larger chelipede may be characteristic of the male sex. 
1 The spinules of the upper orbital margins are foreshortened in an anterior view, and are not shown, therefore, 
in the magnified view of the front (pi. xiii. fig. 2 a). 
2 A. Milne Edwards, tom. cit., p. 289, pi. 1. fig. 5, 1880. 
