478 



THE VOYAGE OF H.M.S. CHALLENGER. 



The terminal pair of pleopoda is about one-third shorter than the telson. 



Habitat. — October 27, 1874, Samboangan, Philippine Islands. Taken at the surface. 

 One specimen (young). 



October 23, 1874 ; off Sibago, Philippine Islands. Two specimens. 



The carapace is oval, smooth, and anteriorly produced to a rostrum that is about one- 

 fourth the length of the carapace. The anterior margin has a large orbital notch, and 

 the fronto-lateral angle is rounded off. 



The pleon is much narrower than the pereion, and has the anterior five somites sub- 

 equal, and except the first armed on the posterior margin with two small backwardly 

 directed teeth, one on each side of the median line. The sixth somite is about equal in 

 length to the four preceding combined, and terminates in two small dorsal teeth. 



The telson (fig. 5z) is about two-thirds the length of the sixth somite, and terminates 

 in the posterior projection of the lateral angles, the cleft between them being armed with 

 five serrate spinules on each side, and one small one in the median line. 



The ophthalmus is large, and supported on a thick and short ophthalmopod. 



The first pair of antenna? has the articulations of the peduncle not clearly defined, 

 and supports only one flagellum, but as this is only rudimentary, the second flagellum 

 may be in an earlier condition, and not yet visible. 



The second pair of antennas has the flagellum subequal in length with the carapace, 

 and within the exuvium, which appears to be entire, the multiarticulate character of the 

 appendage is apparent (fig. 5c); it also supports a scaphocerite that increases distally in 

 breadth, and has the inner margin fringed with hairs, and the outer smooth, rigid, and 

 distally armed with a small tooth. 



The mandibles and first two pairs of siagnopoda have not been examined. 



The third pair of siagnopoda or the masillipedes (fig. 5g) are short, the basis carrying 

 a two-jointed ecphysis, beyond which there are three small joints. 



The first pair of gnathopoda (fig. 5/t) has the coxa stout, the basis long and cylin- 

 drical, and carries distally a short biarticulate ecphysis ; the next joint is short, and the 

 succeeding two are remarkably long, slender, cylindrical, and subequal, and terminate 

 in five or six long hairs. The second pair of gnathopoda (fig. 5i) is short; the basis is 

 here rather more robust, narrows distally, and terminates in a two- jointed basecphysis, 



