NO. 1 HARTMAN : POLYCHAETOUS ANNELIDS 65 



geniculate acicula that taper distally, in addition to entire, narrowly bi- 

 limbate setae. The dorsalmost aciculum is larger than the others, and all 

 decrease in size, proceeding ventrally. Pectinate setae are distally nearly 

 straight, with many fine teeth (pi. 3, fig. 51). 



The proboscidial armature is well developed, the mandibles a little 

 longer than the maxillaiy carriers and forceps together. Mandibles are 

 free from one another for nearly their entire length; the distal calcareous 

 plates are flaring, winglike (pi. 2, fig. 44) ; the long basal ends are dark. 

 The maxillary carriers are broad, basally rounded (pi. 2, fig. 45). On 

 the left side the plates are arranged as follows: I is falcate, II has 8 

 teeth of which the second from the distal end is minute, III has 8 teeth, 

 IV has 7 teeth, and V is a single tooth. On the right side I is similarly 

 falcate, II has 9 teeth of which the second from the distal end is minute, 

 III (with IV fused) has 10 teeth, and V is a single tooth (pi. 2, fig. 45). 



The tube (pi. 16, fig. 334) is coarse, large, thick, externally covered 

 with larger and smaller shell fragments, small sticks, and other debris; 

 it appears untidy; distally it is curved, its external opening probably a 

 lateral vent. 



The dorsal pigmentation pattern (preserved) appears to be unique; 

 on the anteriormost segments, from the peristomial ring, there is a larger, 

 dark reddish brown spot medially, surrounded by a clearer area. A simi- 

 lar, though weaker, pigment is present at the sides in a short, transverse 

 band toward the parapodial bases, across the middle of the segment. A 

 similar pigment sometimes occupies a greater area, but the darker median 

 spot appears to be constant on at least the first few segments. 



The following color note was made from a living specimen (coll. 944- 

 39) from Panama: tentacular ceratophores are grayish lavender, the 

 rings darker, tentacles have bands of grayish lavender, alternating with 

 vinaceous purple. The prostomium is pale; the peristomium is light 

 brownish drab, but its cirri are pale vermilion. The first setiger is dull 

 Indian purple, thereafter light brownish drab. The branchial plume is 

 dull pale yellow, becoming darker or vermilion toward the posterior end; 

 its stem is pale yellow with a rose red spiral stripe. The ventrum is light 

 brownish vinaceous. It is iridescent both above and below. (Noted by 

 Mr. Anker Petersen.) 



D. neotridens resembles D. tridentata (above) in having tridentate 

 hooded hooks in anterior parapodia, but the third tooth is much more re- 

 duced ; it differs further in having a tube that is coarse, untidy (pi. 16, 

 fig. 334), not smooth, annulate. D. neotridens approaches D. cuprea in 

 having pectinate setae that are only slightly asymmetrical and terminate 



