49 



of the rami of the uropods, hut in the shape of the antennal squama and the interesting telson 

 and in the dcvelopment of the second pair of pleopods his species, R, jlagellipes Mig, is so 

 closely related to the form captured by the "Siboga" that I am convinced that the same 

 interesting structure of the uropods is found in his species. 



27. Rhopalophthalmus cgregius n. sp. PI. VI, figs. 3^ — 3/'; PI. VII, figs. \a — \d. 



Stat. 323. February 2425. Sangkapoera-roads, Bawean-island. 12 m. 12 specimens (comprising 

 adults of both sexes, but all badly preserved). 



Description. - Body scarcely as robust as in Siriella aiwmala. Carapace very short, 

 perhaps as short as, or still shorter than, in Hemisiriella, but the bad state of preservation 

 does not allow a more exact judgment as to the length of the thorax. The frontal plate (PI. VI, 

 fig. 3«) is very short, forming a very flat triangle with the vertex blunt; at each lateral end 

 of the plate a short, broad, acute, supraorbital tooth is found, the outer margin of which is 

 much longer than the inner, the upper part of the front lateral margin receding a little behind 

 the lateral end of the margin limiting the frontal plate. Eyes somewhat large, black ; eye-stalks 

 a little longer than broad at the base of the cornea, without tubercle. Antennal squama 

 (PI. VI, fig. ?> a an d PI. VII, fig. 1 ff) similar in both sexes, nearly six times as long as broad, 

 with the margins parallel; the outer margin terminates in a slender denticle scarcely or slightly 

 overreaching the end of the short lobe; the lobe is marked off by a somewhat oblique, very 

 distinct articulation. 



Endopod of first pair of male pleopods (PI. VI, fig. 3/) very oblong, about three times 

 as long as broad ; exopod of second male pleopods (fig. 3 k) more than twice as long as the 

 endopod, with the joints of more than its distal half elongated, increasing in length to the tip 

 and without setae, excepting the last joint, which has two long terminal setae and a third long 

 lateral seta near the end. 



Uropods (PI. VII, fig. 1 c) similar in both sexes, very slender; the exopod somewhat 

 longer than the endopod, with its distal joint more than three times as long as broad; the 

 inner margin of the exopod with the usual feathered setse, while the outer margin, though 

 fineiy serrated, is naked in my specimens, but perhaps the setse (according to Iixig's figure well 

 developed in his species) are lost ; the endopod has short hairs along the outer, long and feathered 

 setae along the inner, margin and besides a single, strong spine near the middle of the inner 

 margin of its proximal joint, while its distal joint is a little shorter than that of the exopod. 



Telson (PI. VII, figs. \c and id) not fully three times as long as broad; a short basal 

 part is considerably widened but without marginal spines ; then the telson is constricted but 

 increases again feebly in breadth to the middle, wherefrom it tapers to the rather broad and 

 broadly rounded end ; somewhat more than half of each lateral margin is armed with about 

 1 5 strong spines increasing gradually and considerably in length posteriorly and each bearing 

 at the base of the inner margin 2 or 3 fine denticles. The end of telson (fig. 1 d) has four 

 very long and extremely robust spines, the outer pair a little longer than the inner; each spine 

 has along each lateral margin a close row of spiniform processes, small near the base and 



SIBOGA-EXI'KDITIE XXXVII. 7 



