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



appendages of the male are similar to those of Notopoides; the vasa deferentia are 

 protruded as short tubular outgrowths. 



The single specimen is an adult male, and gives the following measurements : — 

 Breadth of carapace 14 mm., of fronto-orbital border (from one orbital spine to the other) 

 5 mm., length of carapace 21 mm., of chelipede 23 mm., of last leg ITS mm,, of 

 abdomen 9'5 mm., of first male appendage 7 mm., of external maxillipede 87 mm. 



This species, which must be classed as one of the most interesting Crustaceans in the 

 collection, was discovered more than fiftj' years ago in the Bay of Fort Eoyal, Martinique, 

 by M. C. P. de Freminville, the captain of a French vessel, which was at that time 

 cruising in the West Indies. Only a single specimen was obtained, and it does not 

 appear to have been met with again till its rediscovery by the Challenger on the Brazilian 

 coast. The description and figures originally given by this writer are very inaccurate ; 

 he referred the species to the fossil genus Eryon, to which it does not even bear a 

 superficial resemblance, described the subdorsal legs as forming the second pair, and the 

 antennules escaped his observation altogether. I should have had great hesitation in 

 identifying the Challenger specimen with the Eryon caribensis, were it not that while in 

 Paris, Professor Alphonsc Milne-Edwards drew my attention to a collection of pencil- 

 drawings of Crustacea, in the Library of the Museum of Natural History, in which the 

 Challenger species is unmistakably figured under the name of Eryon trilobatus, and 

 the locality " Caribbean Sea " assigned to it. It seems unlikely that two species were 

 found, so I have adopted the specific name which appears in De Freminville's published 

 paper. 



Habitat. — Off Bahia, 7 to 20 fathoms. 



HIPPIDEA. 



Ilijjpcs, Latreille, Eegne Anim. de Cuvier, Ire 6d. t. iii. p. 28, 1817. 

 Hippicns, Milne-Edwards, Hist. Nat. des Crust., t. ii. p. 200, 1837. 

 Hippidea, De Haan, Crust. Japon., p. xxii, 1850. 



Dana, U.S. Explor. Exped., vol. xiii., Crust., part. i. p. 400, 1852. 



Stimpson, Proc. Acad. Nat. Sei. Philad., p. 67, 1858. 



Miers, Catal. New Zealand Crust, p. 58, 1876; Journ. Linn. Soc. Lond. (ZooL), vol xiv. 

 p. 312, 1877. 



Haswell, Catal Au.stral. Crust, p. 151, 1882. 



Carapace ovate or subquadrate, comparatively smooth, the regions ill-defined; the 

 frontal margin broad. Ambulatory limbs with flattened dactyli ; the last pair slender 

 and filiform, folded under the penultimate pair. Abdomen semi-extended, composed of 

 six segments (the fifth and sixth fused), the penultimate with a prominent pair of 



