P^ICILASMA FISSA. Ill 



end into a very narrow, short, imbedded disc, (or rather 

 tooth,) which is itself a little curved downwards and 

 blunt at the end. 



Peduncle very narrow, about half as long as the 

 capitulum ; yellow, finely beaded, plainly ringed, without 

 spines. 



Mouth. — Labrum, with a row of minute teeth ; palpi 

 narrow. Mandibles with all the lower part narrow ; of 

 the four teeth, the second and third are narrow, the 

 fourth is pectinated and placed very close to the inferior 

 angle, which is produced into a long thin tooth. Maxillae 

 unknown. 



Cirri. — First pair lost. The arrangement of the spines 

 on all is most abnormal, PL X, fig. 29 : dorsal tuft long, 

 arranged in a transverse line and seated in a deep notch ; 

 in the sixth cirrus, the spines on the lower segments are 

 fine, those on the upper segments are thick and claw- 

 like, mingled with some fine spines ; in the four anterior 

 cirri the spines of the dorsal tufts are even thicker 

 and more claw-like. On the anterior faces, also, of all 

 the segments the spines form a single row; they are 

 shorter than those composing the dorsal tuft ; hence the 

 spines on each segment are arranged in a circle, inter- 

 rupted widely on the two sides : this arrangement is 

 common to all five posterior cirri. Second cirrus, with 

 the anterior ramus one third longer and thinner than 

 the posterior ramus (this is the reverse of the usual 

 arrangement) ; this longer ramus equals in length the 

 sixth cirrus. Third cirrus, with the anterior ramus con- 

 siderably longer than the posterior ramus ; in the three 

 posterior pair of cirri, also, the anterior rami are a little 

 longer than the posterior : except in length, there is 

 little difference of any kind between the five posterior 

 pair of cirri. Pedicels of the cirri long; rami rather 

 short ; segments elongated, not protuberant. 



Caudal Appendages nearly as long as the pedicels of the 

 sixth cirrus, thickly clothed with very fine bristles, like a 

 camel's-hair pencil brush. 



