REPORT ON THE CRUSTACEA MACRURA. 387 



corresponding with its position. The ophthalmus is more orbicular, and it is larger in 

 diameter than the stalk, whereas in Sergestes cornutus the ophthalmopod is pear-shaped, 

 gradually lessening from the broadest diameter to the base. The first pair of antennae, 

 as shown in Kroyer's figure, has the flagellum more than twice the length of the animal, 

 whereas in this specimen it is less than half the length ; but it is not improbable 

 that so slender an organ may have been broken off, without any very obvious trace 

 of the accident being apparent. 



The rhipidura in Sergestes cornutus has the outer margin of the external plate armed 

 with a distinct tooth, whereas in the Challenger specimen it is feeble and not clearly 

 defined. 



Sergestes japonicus, Spence Bate (PI. LXX. figs. 1, 2). 



Sergestes japonicus, Sp. B., loc. cit., p. 194. 



Anterior surface of the carapace projecting into a short dorsal rostriform crest ; the 

 rest of the carapace smooth. Pleon smooth, laterally compressed. The ophthalmopod 

 long and subcyhndrical, the ophthalmus being scarcely broader than the stalk. 



The first pair of antenna? has the peduncle half as long as the carapace, and terminates 

 in one long and one minute flagellum, the latter being scarcely half as long as the 

 terminal joint of the peduncle. Synaphipod of the mandible two-jointed, long and 

 slender, reaching as far forward as the extremity of the peduncle of the second pair of 

 antennas. 



The pereiopoda, except the last two, are broken off. 



The pleopoda are generic in character, and offer nothing for specific distinction. 

 The rhipidura is long and narrow ; the telson is about two-thirds the length of the 

 outer ramus. 



Habitat.— Station 232, May 12, 1875; lat 35° 11' N., long. 139° 28' E.; off the 

 southern coast of Japan ; depth, 345 fathoms ; bottom, green mud ; bottom temperature, 

 41°"1. One specimen. Both trawl and dredge were used. 



Length (female), 50 mm. (2 in.). 



Station 207, January 16, 1875 ; lat. 12° 21' N., long. 122° 15' E. ; off Manila ; depth, 

 700 fathoms ; bottom, blue mud ; bottom temperature, 51°'6. Two specimens (females). 

 Trawled. 



Length, 27 mm. (1 - 1 in.). 



The texture of this species is soft and membranous, the tissues being exceedingly 

 transparent and reticulate. The dorsal median line is elevated anteriorly into a small 

 laterally compressed crest, which projects forwards to a point. 



The ophthalmopod is nearly as long as the first joint of the peduncle of the first pair 

 of antennas, and supports an ophthalmus that is black in colour, and not broader than 



