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



very broad, very long, thick, ovate, and terminates in a short pollex and a curved 

 short dactylos. The second pair of pereiopoda is slender and multiarticulate ; the third 

 and fourth pairs are more robust than the second, and the fifth pair more slender than 

 the preceding. 



The pleopoda are long and biramose, and the rhipidura is broad, and fringed with 

 hairs and strong teeth. 



This genus probably belongs to the same group as that which Milne-Edwards calls 

 the second, or those species which carry a pointed rostrum, viz. : — 



B. A large spine fixed upon the external border of the basal joint of the 

 second antennae and directed forwards. 



In this group Milne-Edwards places Alpheus spinifrons, Milne -Edwards, Alpheus 

 heterocheles, Say, Alpheus minus, Say, Alpheus villosus (Olivier), and Alpheus 

 diversimanus (Olivier). 



Paralpheus diversimanus (Olivier) (PI. CIL). 



Palemon diversimanus, Olivier, Encycl., t. vii. p. 663. 



„ villosus, Olivier, loc. cit., t. viii. p. 664. 



Alpheus villosus, Milne-Edwards, Hist. Nat. Crust., t, ii. p 354. 



,, diversimanus, Milne-Edwards, loc. cit., p. 355. 



Body of the animal generally granulated and papillose, sparsely covered with rigid 

 hairs. 



The carapace is produced anteriorly into a rostrum that reaches as far forwards as 

 the extremity of the first joint of the first pair of antennae, and in the median dorsal line 

 a second point projects above the orbits. The frontal margin projects over the ophthal- 

 mopoda, and is elevated into a prominent tubercle which is anteriorly armed with a sharp 

 pointed tooth directed forwards. The branchial region is deeply produced on each side. 



The first pair of antennas has the first joint armed with a stylocerite that reaches 

 nearly to the extremity of the joint ; the second joint is cylindrical and a little longer 

 than the first ; the third joint is short and supports two slender flagella, of which the 

 upper is the more robust for the greater part of its length, and then it suddenly becomes 

 more slender. 



The second pair of antennae has the penultimate joint of the peduncle armed with 

 a long and slender tooth that reaches nearly to the extremity of the scaphocerite, 

 which also terminates in a sharp point and carries on the inner side a narrow plate that 

 is separated for some distance from the rigid outer styliform extremity. The ultimate 

 joint is cylindrical and reaches a little beyond the extremity of the scaphocerite, and 

 carries a slender tapering flagellum that is as long as the animal. 



The mandible has the psalistoma distinct from the molar process, broad, convex, and 

 evenly serrate, and the synaphipod is broad, flat, spatuliform, and fringed with hairs. 



