370 L1THOTRYA TRUNCATA. 



valves are dirty white. The sack is (after having been 

 long kept in spirits) pale coloured, excepting a small 

 purple space, between the scuta and another over the 

 carina. The three posterior segments of the thorax and 

 portions under the second and third cirri, the tropin, the 

 pedicels and the anterior faces of the segments (especially 

 of the basal segments in the second and third cirri), and a 

 spot on their dorsal surfaces, and the penis are all coloured 

 dark purplish- black. The prosoina is pale coloured. 



Mouth. — Crest of labrum with a row of bead-like teeth 

 and hairs. Palpi bluntly pointed, with neither margin 

 hollowed out. 



Mandibles, with eight pectinations between the first 

 and second main teeth, and three between the second 

 and third teeth ; inferior angle coarsely pectinated, with 

 a central spine much longer than the others ; the distance 

 between the tips of the first and second main teeth, is 

 about equal to that between the tip of the second tooth 

 and of the inferior angle. 



Maxilla.— Under the two upper long spines (associated 

 with some smaller ones), there is a slight and wide hollow ; 

 and the whole inferior edge obscurely forms two blunt 

 points, with the spines on the lower projection smaller 

 than the upper spines. 



Outer Maxilla, considerably concave in front, with the 

 spines almost discontinuous in the middle part. 



Cirri. — First pair rather far separated from the second 

 pair. The segments of the three posterior cirri bear three 

 or four pairs of main spines, and are otherwise charac- 

 terised like the foregoing species. First cirrus, with its 

 anterior ramus much thicker than the posterior ramus, 

 and of nearly equal length ; all the segments, except the 

 two terminal ones, thickly clothed with serrated spines. 

 Second cirrus considerably shorter than the third cirrus : 

 anterior ramus with the seven basal segments very pro- 

 tuberant, and paved with bristles, and the four terminal 

 ones on the usual structure ; posterior ramus, w T ith the five 

 basal segments paved (but much less thickly than in the 



