198 . THE SCHIZOPODA. 



Remarks. — As already stated, this species is on the whole allied and similar 

 to A. grossa, but the male is easily distinguished by the quite different shape of 

 the rostrum, by having the third antennular joint conspicuously longer in pro- 

 portion to its breadth, and by the above-mentioned differences in the sexual 

 organ terminating the exopod of third pair of pleopods. 



GASTROSACCUS Norman (1869). 



The "Albatross" secured several specimens in 1900, but none were found 

 among the material of 1904-1905. 



18. Gastrosaccus pacificus, sp. nov. 



Plate 2, figs. 3a-3g. 



Butaritari, Gilbert Islands. Jan. 6, 1900. Lagoon. Surface. Light. 8 .specimens (3 (1 Type) adult 

 males, 5 females with marsupium, 1 immature female). "Albatross." 



Description. — Frontal plate, eyes, antennulae, and antennal squama (fig. 3a) 

 nearly as in G. indicus H. J. H. (1910). — Male pleopods in the main as in G. 

 indicus, but differing in some particulars. First pair (fig. 3b) with the endopod 

 very slender, not one third as long as the exopod, which has the distal third 

 divided into four joints. Second pair (fig. 3c) only a little more than half as 

 long again as the first; the peduncle with second joint almost four times as long 

 as broad; the endopod more than half as long as the exopod, with the distal 

 major part of the proximal half considerably expanded on the outer side and 

 the expansion distally terminating in a .sharp, somewhat acute angle, while 

 the distal part of the endopod is slender with a single articulation; the exopod 

 is about as in G. indicus. Third pair (fig. 3d) with the endopod not distinguish- 

 able; the exopod is extremely elongate, but its distal portion is lost in all the 

 specimens; the most proximal part of the exopod is strongly thickened, twice 

 as long as broad and on the outer side distally produced into a rather short 

 triangular process directed strongly outwards; somewhat beyond that thick- 

 ened part three small spines are found. Fourth (fig. 3e) and fifth (fig. 3f) 

 pairs nearly as in G. indicus; both rami unjointed, the exopod considerably 

 more slender and on fourth pair slightly, on fifth pair considerably, longer than 

 the endopod. 



Uropods (fig. 3g) nearly as in G. indicus; the exopod with 11 or 12 marginal 

 spines, most of them long, longer than in G. indicus. Telson nearly two and a 

 half times as long as broad, with 10-12 spines along each margin, the terminal 



