Leodicidce from Fiji and Samoa. 161 



abnormality. The left half of the forceps has a shorter base and longer fang than the 

 right; the base has 4 well-marked teeth. The first pair of plates are asymmetrical, 

 the right one much shorter than the left, and its margin has 7 rounded teeth, while 

 the left one is longer than the forceps, with at least 10 large, sharp teeth. The second, 

 third, and fourth pairs of plates are symmetrical, the second and third each has 4 and 3 

 teeth respectively, while each one of the fourth pair has one tooth. The mandible 

 (plate 8, fig. 9) is large as compared with the maxilla, its halves fused for more than 

 half their length. 



In character of prostomium, parapodia, and setae this species is closely alUed to 

 A. attenuata Treadwell (1906, p. 1172, fig. 62), but differs in the character of the jaw. 

 In the structure of the jaw it approaches more closely to A, munda Chamberlin (19196, 

 pp. 258-259), but differs in the number of teeth on the maxillary plates. 



The type is in the American Museum of Natural History. 



Genus DRILONERIES Claperede. 

 E. Clap6r6de, Les Annelides Chaetopodes, etc., 1870, p. 399. 



Body elongated, slender, without prostomial appendages. Parapodia with rudi- 

 mentary dorsal cirri, but frequently in anterior somites the parapodium reduced or 

 practically absent. No compound or hooked setae. Prostomium always very much 

 flattened dorsoventrally, so that vertical diameter at the base is little greater than at 

 apex. Maxilla with long, slender carriers, forceps, and three or four pairs of plates, 

 the latter feebly developed as compared with Arabella. Mandible absent or rudi- 

 mentary. 



Drilonereis can usually be distinguished from Arabella, to which it bears a very 

 close resemblance, by the peculiar flattened prostomium (see plate 7, fig. 14). 



Drilonereis lumbricus, new species. 

 Plate 7, figures 13 to 15; plate 8, figure 10; text-figures 63 to 65. 



Individuals of this species are large for the genus Drilonereis, measuring 150 mm. 

 in length, with a prostomial width of 1 mm. and a body diameter of 2 mm. in the 

 widest part. Apparently the diameter becomes smaller toward the posterior end, 

 but the single specimen at my disposal was too badly preserved posteriorly to be 

 certain on this point. 



The prostomium (plate 7, fig. 13) has an oval outline as seen from above and is 

 narrower at the posterior end, where it fits into the anterior margin of the peristomium. 

 In preserved material the prostomium is bent ventrally so as to make an angle with 

 the main axis of the body. On its median dorsal line is a relatively deep depression 

 extending nearly the whole length of the prostomium. The peristomium is short 

 on the dorsal surface, but extends forward on either side, so that the lateral length is 

 more than double that of the dorsal. Ventrally it is thrown into a number of folds 

 (plate 7, fig. 14). Near the posterior margin on the dorsal surface is a depression, 

 the nuchal organ. 



The anterior somites for about one-quarter of the whole body are smooth, highly 

 iridescent, and greatly resemble an earthworm in general appearance. Behind this 

 region the body-color is a dirty brown, but this may have been in part due to imperfect 

 preservation. Apparently the pygidium is very narrow. The first setae arise in a 

 tuft on the side of somite 3, but the first appearance of anything that could be called a 

 parapodium is on somite 30. Behind this region parapodda are clearly to be seen, but 

 are never very prominent. Anteriorly each (plate 7, fig. 15) has a posterior lobe, a 

 single stout acicula, and a tuft of simple bilimbate setae curved at the end. Owing to 

 poor preservation no satisfactory preparation of the parapodia could be obtained, 

 and the figure from the forty-fifth somite is the best I could get. Farther posteriorly 

 the acicula becomes relatively smaller, the shafts of the setae elongate, the bilimbate 



