1 1 



Carina narrow, broader at the lower part which is distinctly carinated, terminating in 

 a spatula-shaped disc which is embedded between capitulum and peduncle (PI. I, fig. 7 and -ja). 



Peduncle short, about half the length of the capitulum, cyündrical ; narrow near the 

 place of its attachment to the capitulum, swollen about the middle of its length. Surface with 

 narrow rings indicated by darker chitinous transverse rings. 



Si ze. The capitulum of the largest specimen collected was 11,6 mm. in length. The 

 other specimens are however considerably smaller. 



The study of the animal contained within the capitulum has yielded the following results: 



Mouth. In general as in the other species of the genus, for example, as in P. dubium. 

 Mandibles with a relatively greater distance between the first and second teeth, second, 

 third and fourth nearer to one another on the other hand. Maxillae with no larger spines 

 in the notch beneath the three great upper spines, with five or six slender spines on the slope 

 at the other side of the notch. The spines on the inferior upraised part of the maxilla slightly 

 smaller and less numerous (about 10) than in P. dubium. 



Cirri. First pair at a distance from the second, with nearly equal rami each divided 

 into five segments. Outer surface of the segments with numerous and long hairs, a transverse row 

 of rather strong hairs or spines near the end of the third and fourth segments and terminallv 

 on the fifth segment also. 



The other cirri as in the other species of the genus. The number of spines on the front 

 side of the segments of the cirri N" II — VI is as a rule four pairs, a fifth pair being often 

 indicated by a couple of extremely short hairs. The number of spines on the last segments is 

 smaller. The number of the segments in the cirri II — III is 10 and 11, in the cirri IV — VI 

 1 1 and 1 2. 



The eau cl al appendages are slender, about as long as the first segment of the 

 pedicel of the sixth cirrus. They bear a dense tuft of very long hairs along the outer side in 

 the last third part of their length (PI. I, fig. 8). 



Penis thick, ringed especially about the middle of its length, terminating in a much 

 narrower and curved part. Extremely delicate and sparse hairs on the surface, a tuft of slightly 

 stronger hairs at the extremity. 



H. M. S. "Siboga" collected this species twice, viz. once five specimens at: 



Stat. 253. December 10, 1899. Lat. 5°48.2S., Long. I32°I3'E. Depth 304 m. Bottom: gray 

 clay, hard and crumbly. 



and half a dozen specimens at : 



Stat. 12. March 14, 1899. Lat. 7°i5'S., Long. U5°i5'.6E. Depth 2S9 m. Bottom: coarse 

 sand with broken shells. 



Of the latter specimens one was attached to a small piece of the scale of a Crustacean. 



General Re mark. This species belongs to the same section of the genus as Darwin's 

 P. fissum and the species P. amygdahim, P. Icnticula, tridens and vakans of Auriviluus: all 

 species with 7 valves, the scutum in each being formed of two closely approximate segments. 

 The very characteristic excavation of the scutal margin of the tergum and the spatula-shaped 



