280 ZOOLOGISCHE MEDEDEELINGEN — DEEL HI. 
the postrostral carina; it is armed dorsally with 27—33 fixed teeth, of 
which 5, rarely 4 or 6, are planted on the carapace. Orbital spine small, 
branchiostegal spine still smaller. 
Abdomen little longer than carapace and rostrum combined. Posterior 
border of 3rd tergum convex, little prominent. Sixth- abdominal somite 
about one and a half to almost twice as long as fifth. Telson almost as 
long as or slightly longer than the two preceding somites combined. 
Antennal scale a little longer than two-thirds the length of the cara- 
pace, 4-times as long as wide. 
Posterior lobe of exopodite of 2nd maxilla rounded. Seventh joint of 
2nd maxillipeds applied as a strip to the 6th, six times as broad as long. 
Exopodite of external maxillipeds well developed. 
Legs of 2nd pair slender, equal. Of the three posterior legs the meri 
gradually diminish a little in length, the carpi and propodi on the con- 
trary increase in length from the 8rd to the 5th; the 5th legs show 
therefore the greatest length, though they extend a little less forward 
than the preceding. 
Plesionika assimilis n. sp. 
Stat. 51. April 19. Madura-bay and other localities in the southern 
part of Molo-strait. 54—90 m. Bottom fine grey sand; coarse sand with 
shells. 12 specimens, viz. 3 males, 8 females, 7 of which are egg-laden, 
and 1 young specimen. 
A new species closely related to Plesion. rostricrescentis (Sp. Bate), 
Plesion. binoculus (Sp. Bate) and Plesion. exigua (Rathbun). 
Dorsal crest beginning at the anterior third of carapace, low, not so 
much elevated as in Plesion. binoculus and not so strongly arched as in 
Plesion. rostricrescentis ; the rostrum, which is about one and two-thirds 
to one and three-fourths as long as the carapace, runs at first almost 
horizontally forward, being but little depressed, as far as the distal ex- 
tremity of 2nd antennular article and hence it is strongly upturned. The 
rostrum, which is slender, tapering and not widened at base, is armed 
dorsally with 7 or 8 proximal and 3 or 4, rarely 2, teeth near the tip, 
the proximal and the distal teeth being separated by a more or less 
long, smooth and unarmed interspace; the first five teeth are movable 
and of these the 5th stands above the orbital. margin or just beyond it; 
the lower margin is armed with 11, rarely 10 or 12, teeth that stand 
to near the tip. Antennal spine small, branchiostegal spine minute. 
Abdomen, telson included, 3-times as long as carapace (in Plesion. 
exigua nearly 4-times). Posterior margin of 3rd tergum a little convex. 
Sixth somite in the adult one and a half as long as fifth, telson one 
