i 29 



tip of the rostrum is broken off, it reaches still a little bevond the antennal scale; there are 

 proximally 4 movable teeth that slightly increase in length from the i st to the 4 th , the 5" 1 tooth 

 stands above the orbital margin and is foliowed by five that become gradually smaller, while 

 one observes after a short distance still 3 much smaller teeth, which also diminish in size. 

 There are 7 teeth on the lower margin, the i st near the distal end of the antennular peduncle, 

 and these teeth become also gradually smaller. The left leg of the 2 nd pair that reaches by 

 the chela and two-fifths of the carpus beyond the antennal scale, is a little longer than 

 the right, of which only the chela extends beyond the scale; the carpus of the left leg is 7 mm., 

 that of the right 6 mm. long. The three posterior legs are very incomplete. 



The male from Stat. 253 is (Fig. 27e) 45,5 mm. long (rostrum 10 mm., carapace 7,5 mm., 

 abdomen 2S mm.) from apex of rostrum to tip of telson, the much larger female 48 mm. from 

 orbital margin to tip of telson (carapace 10 mm., abdomen 38 mm.); the male from Stat. 95, 

 finally, measures 42 mm. (rostrum probably 8,6 mm., carapace 7,4 mm., abdomen 26 mm.). 



General distribution: Hawaiian Islands (Rathbun). 



5. Plesionika unidens Bate. PI. XI and XII, Fig. 28 — 28/;. 



Plesionika unidens C. Spence Bate, Report Challenger Macrura, 1888, p. 648, PI. CXIII, fig. 4. 

 Plesionika affinis A. R. S. Anderson. in: Annals Mag. Nat. Hist. Ser. 7, Vol. III, 1899, 



p. 285 (teste A. Alcock). 

 Pandalus (Plesionika) unidens A. Alcock, Descr. Catal. Indian Deep-Sea Crustacea. Calcutta 



1901, p. 97. 



Stat. 12. March 14. 7°i5'S., U5°i5'.6E. Bali Sea. 289 m. Bottom mud and broken shells. 



1 adult, eggdaden female. 

 Stat. 65a. May 6. Very near Station 65 (7°o'S., I20°34'.~5 E.). From 400 m. Bottom pale, 



grey mud, changing during haul into coral bottom. 1 adult, eggdaden female. 

 Stat. 253. Dec. 10. 5°48'.2 S., I32°I3'E. West of Kei-islands. 304 m. Bottom grey clay, hard 



and crumbly. 1 specimen of medium size, without eggs, probably female. 



Plesionika unidens Bate differs from all the other species of this genus by the characteristic 

 carination (Fig. 28^) of the 3 vd abdominal tergum, which is compressed and carinated dorsally in the 

 middle, the carina ending abruptly, like a tooth, nearly at the posterior fourth, while at the anterior 

 fourth it gradually passes into the surface of the tergum. This species is moreover distinguished 

 by the existence of a solitary tooth on the upper border of the rostrum, somewhat behind the 

 apex, while the rest is smooth until near the base. Unfortunately in the female from Stat. Ó5 a 

 the rostrum is broken off at the level of the distal extremity of the antennular peduncle, while 

 in the two other specimens the rostrum is also broken off near the tip, so that the solitary 

 tooth is wanting. Xevertheless these specimens should, no doubt, be referred to Pies. unidens 

 Bate, because in the other characters they apparently agree with this species. 



Measured dorsally, the carapace of the female from Stat. 12 (Fig. 2S<?) proves to be 

 13,3 mm. long, the rostrum, as far as preserved, 22,5 mm. According to Spexce Bate the 

 rostrum should be twice as long as the carapace, but in the fïgure 4 on Plate CXIII of his work it 

 appears almost 3-times as long. Assuming the same relative length for the rostrum of the female 

 from Stat. 12, the rostrum has been ^7 mm - ^ on S m trns specimen and the distance between the 



SIBOGA-EXl'EDITIE XXXIX aK 17 



