176 
THE VOYAGE OF H.M.S. CHALLENGER. 
This species is easily recognised by its flattened pubescent carapace, whose postero- 
lateral angles are spinuliform ; the merus or arm of the chelipedes bears two spines on 
its posterior margin. There is commonly, but not invariably, a dark-coloured spot at 
the distal extremity of the terminal joint of the fifth leg. 
Adult 
Lines. 
Millims. 
Length of carapace, .... . . 
n 
16 
Breadth of carapace to base of lateral epibranchial spine, 
ii* 
24-5 
Adult males and females in the series have, attached to the ventral surface of the 
abdomen, a Rhizocephalous parasite allied to or identical with Scicculina. 
Neptunus ( Amphitrite ) tuberculosus, A. Milne Edwards. 
Neptunus tuberculosus, A. Milne Edwards, Archiv. Mus. Hist. Nat., vol. x. p. 333, pi. xxxi. 
fig. 5, 1861. 
Arrou Island, September 18, 1874 (a small male). 
In this specimen the teeth of the antero-lateral margins are somewhat unequally 
developed, usually alternately larger and smaller ; the spines of the chelipedes are very 
small, that near the wrist being reduced to a tubercle, as in the figure of Milne Edwards. 
g . . Lines. Millims. 
Length of carapace, . . . . . . . 4J 10 
Breadth of carapace to base of lateral epibranchial spine, nearly . 6J 13 
Neptunus (. Amphitrite ) rugosus, A. Milne Edwards. 
Neptunus rugosus, A. Milne Edwards, Archiv. Mus. Hist. Nat., vol. x. p. 335, pi. xxxiii. 
fig. 3, 1861. 
A small male, obtained in Torres Strait (August 1874), and an adult male 
dredged at the Philippines, lat. 11° 87' 0" N., long. 123° 31' 0" E., in 18 fathoms 
(Station 208), are referred to this species ; also a female dredged in the Celebes Sea, in 
10 to 20 fathoms, lat. 6° 54' 0" N., long. 122° 18' 0" E. (Station 212). 
The two latter are distinguished from the types of Milne Edwards’ description and 
figure, from Shark Bay, West Australia (preserved in the collection of the British 
Museum), by the much less strongly and distinctly tuberculated carapace, the much 
shorter lateral epibranchial spine, and the longer chelipedes, distinctions which I suppose 
to be due to the greater age of the Challenger specimens. 
This species is distinguished (as pointed out by Professor A. Milne Edwards) from all 
of its congeners, except Neptunus tenuipes, de Haan, by having only five frontal teeth, 
and from Neptunus tenuipes by the dentiform, not rounded, postero-lateral angles of the 
carapace. Except in this latter important character, the adult Challenger specimens 
