LEODICIDiE OF THE WEST INDIAN REGION. 91 



Genus NICIDION Kinberg. 



J. G. Kinberg, Annulata Nova, etc., 1864, p. 564. 



Defined by Kinberg as having the general form of the Eunicidse (Leodicidse), but 

 without gills. The jaw structure resembles that of Leodice. The parapodial develop- 

 ment is feeble, especially throughout the middle and posterior regions. Small animals, 

 sometimes confused with young Leodice in which the gills have not appeared, but easily 

 distinguished because of the feeble parapodial development. 



Nicidion kinbergii Webster. 



(Plate 6, figures 5 to 8; text-figures 324 to 332.) 



Nicidion kinbergii Webster, 1884, p. 320, plate 12, figures 81-88. 

 Nicidion kinbergii Treadwell, 1910, pp. 7-9, figures 15-22. 



Webster's description was based on a single incomplete specimen collected in Ber- 

 muda by Goode. Later collections in the Dry Tortugas enabled me to add to his descrip- 

 tion, but my work was based on preserved material. What follows is written after the 

 study of a large number of living animals and is intended to correct some errors in my 

 earlier description as well as to greatly extend it. 



The average specimen measures about 80 mm. in length, with a peristomial width 

 of 2 mm., and about 140 somites. 



The color is very variable, though the general body-color is usually a pale straw, 

 with in most cases a considerable amount of reddish-brown pigment. Toward the 

 middle of the body this pigmentation extends on to the ventral surface, but in succeeding 

 somites it becomes less noticeable, to again increase in amount on the last four or five 

 somites. In life the dorsal blood-vessel is very prominent, and the color of the middle 

 and posterior ends of the body is much darkened by the accumulation of fecal matter 

 in the intestine (plate 6, figures 5-8). The apices of the tentacles are white, and the 

 dorsal surface of the peristomium may, as in figure 6, be covered with blotches of brown 

 and yellowish white. Somites 4 and 5 are usually uncolored dorsally, though on one 

 specimen somites 6 and 7 were thus uncolored. The dorsal surface of the prostomium, 

 in the most deeply pigmented individuals, has two bands of pigment, beginning at the 

 bases of the paired tentacles and extending to the anterior edge of the prostomium. 

 From here each is continued as a narrower band, the two uniting along the ventral 

 surface of the prostomium. Behind the tentacles are two colored bands making an 

 X-shaped figure on the dorsal surface of the peristomium (plate 6, figure 6) and leaving a 

 prominent colorless spot behind the median tentacle. With the exception of the fifth 

 and sixth (or in some specimens the sixth and seventh), the dorsal surface of the anterior 

 part of the body is densely pigmented and this is continued as anastomosing brown 

 areas as far as the middle of the body. 



The tentacles (plate 6, figures 5 and 6) are nearly equal in length, not longer than 

 the peristomium, the outer paired ones being slightly shorter than the others. There is 

 one pair of black eyes. The prostomium is bilobed, but the lobes are bent ventrally, 

 so that they scarcely show from the dorsal surface. The peristomium is as long as the 

 following three somites; the somites immediately following it are rather short, but toward 

 the posterior end they become much longer (plate 6, figure 5). The nuchal cirri are 

 short and slender, not more than half as long as the peristomium, and the dorsal cirri 

 are all short. There is generally one pair of stout anal cirri (plate 6, figure 8), though 

 this number is not invariable. Some have four, which is probably the normal number. 



The first parapodium has prominent dorsal and ventral cirri (text-figure 324) and 

 a small post-setal lobe. Succeeding parapodia as far as the fifth are like this in form, 

 but behind this the ventral portion of the cirrus becomes much swollen and attached 



