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



the supraorbital spines in length, separated at the base by a partition ; the first joint 

 dilated, the second and third cylindrical. Antennse rudimentary, not equalling the ocular 

 peduncles in length ; the first joint narrow and about equal to the third in length, the 

 second twice as long. Ocular peduncles very long and slender, cylindrical, turned for- 

 wards, diverging in the same way as the supraorbital spines. External maxillipedes with 

 the inner margin of the ischium and merus pilose, not spiny, the outer border of the 

 latter joint slightly concave. Legs very long, slender, and cylindrical, the fifth pair of 

 small size and subdorsal in position. Abdomen folded under the thorax, composed of 

 seven segments in the male, of five in the female ; five pairs of abdominal appendages 

 present in the female. 



This very characteristic genus includes four species, viz., LatreilUa elegans, Roux, 

 from the Mediterranean and east coast of the United States, LatreilUa valida and 

 LatreilUa phalangium, both of De Haan, from the Japanese and neighbouring seas, and 

 a fourth from the Australian coasts, described below. 



LatreilUa valida, De Haan. 



LatreilUa valida, De Haan, Crust. Japon., p. 107, tab. xxx. fig. 1, 1850. 

 Habitat. — Station 209, oif Zebu, Philippine Islands ; depth, 95 fathoms ; bottom, 

 blue mud. 



A female with ova is apparently referable to this species. It corresponds closely to 

 the original description, with the exception that the merus of the chelipedes is three- 

 and not five-spined ; the supraorbital spines also exhibit a minute spinule on the inferior 

 surface, whereas they are stated by De Haan to be entire. 



LatreilUa australiensis, n. sp. (PL II. fig. 4). 



Characters. — Carapace subtriangular, the frontal region narrow. The rostrum is of 

 small size, considerably deflexed and acute ; the supraorbital spines are slightly more than 

 half the length of the ocular peduncles, with a slight downward curve, and two to three 

 minute spinules are present on the outer surface in the female. The surface of the 

 carapace is irregular and somewhat glabrous, the regions fairly marked but without 

 spines. The buccal or subhepatic swelling is prominent, but unarmed in both sexes. 



The ocular peduncles have the basal joint remarkably long and slender, the cornese 

 dilated. The antennules are about equal in length to the supraorbital spines, their basal 

 joint subglobose. The antennse are remarkably short and slender, apparently not 

 equalling the antennules (the imperfect nature of the specimens renders this point 

 doubtful). The epistome is smooth and lengthened Out antero-posteriorly. The external 

 maxillipedes have the merus and ischium subequal in length ; the former presents a 



