i37 



I sacrificed the smaller specimen in order to investigate the structure of the animal's body 

 and with regard to this the following may find a place here. 



The body is much flattened and the distance between the mouth and the adductor 

 scutorum muscle is large. 



The mouth is not bullate ; the crest of the labrum is surmounted by 40 — 50 extremely 

 small conical teeth. Numerous delicate hairs, directed towards the mandibles, are disposed on 

 the surface. P a 1 p i rather short, conical, with numerous hairs on the outer side and at the extremity. 



Mandible (PI. XIII, fig. 5) with three teeth and inferior angle pectinated as usual. 

 The upper margin of the third tooth has a couple of additional small teeth and the upper 

 (or anterior) margin of the inferior angle is serrated with about five sharply pointed teeth, the 

 size of which increases from above downwards. Distance between tips of first and second teeth 

 about one and a half times the distance between second and third. 



Maxi 11a (PI. XIII, fig. 6) with the three relatively strong upper spines ; the notch 

 is not deep, but rather wide, and has one short spine at the upper margin near the three 

 upper spines, and two short spines at the inferior margin, which is the upper margin of the 

 step-formed projection. The latter has about 6 spines along the outer edge, one of which is 

 longer and slightly stouter than the others. 



The outer maxillae have the interior surface feebly lobed, the outer clothed with 

 numerous rather long and curved bristles. 



Cirri. Cirrus of first pair standing near the mouth at some distance from the other 

 pairs. This distance, however, is smaller than in the other species of the genus. Rami very 

 unequal in length : the shorter is considerably broader and has 8 — 9, the longer has narrower 

 segments the number of which is 13 — 14. 



Cirrus of second pair has the longer ramus about twice as long as the other; the 

 latter has 6 — 7 somewhat broader, the former 13 — 14 slightly longer and narrower segments. 

 The distal segments of the shorter ramus short and square at the tip. 



The cirri of the posterior pairs have numerous slightly elongated segments ; as a rule 

 they are not protuberant in front; they bear at that side two pairs of slender spines and a 

 third pair of much smaller spines. The dorsal tuft has one long and a few shorter and more 

 delicate spines. The cirri of the 4 th — 6 th pairs are longer than those of the third pair and still 

 increase in length from the 4 th to the 6 th . The rami of the last pair are composed of 23 — 24 

 segments. 



Caudal appendage very long, about half the length of the cirrus of the last pair. 

 Number of segments 2 1 . Length of last segments (PI. XIII, fig. 7) more than six times their 

 breadth. Numerous delicate spines are disposed at the extremity of each segment. 



This species was dredged by H. M. S. "Siboga" at the following places: 



Stat. 52. April 20, 1899. Lat. 9°3'.4S., Long. ii9°56'.7E. Depth 959111. Bottom: globigerina 

 ooze. One specimen, attached to a bundie of siliceous needies of a sponge ? 



Stat. 170. August 26, 1899. Lat. 3° 37.7 S., Long. i3i°26'.4E. Depth 924 m. Bottom: fine 

 grey mud. One smaller specimen, attached to a glass needie. 



General Remarks. This is a very characteristic species. It is recognisable at once by 



9 



SIBOGA- EXPEDITIE XXXI a. l8 



