. mmT O Remarks. The largest of the two incomplete speci- mens measures 13 mm. by i mm. including the feet and has about 65 chaetigers. The colour in spirit is a pale brown. The prostomium is deeply incised in front and the tentacles are short, the median, which is the longest, barely reaching to the 2nd chaetiger. The tentacular cirri are so small as easily to be overlooked. The flattened area of the body with the short crowded segments extends from about the 5th to the 40th segments, about ten segments further back than in Crossland's (1904, p. 327) Nicidion gracilis. More- over, the change
. mmT O Remarks. The largest of the two incomplete speci- mens measures 13 mm. by i mm. including the feet and has about 65 chaetigers. The colour in spirit is a pale brown. The prostomium is deeply incised in front and the tentacles are short, the median, which is the longest, barely reaching to the 2nd chaetiger. The tentacular cirri are so small as easily to be overlooked. The flattened area of the body with the short crowded segments extends from about the 5th to the 40th segments, about ten segments further back than in Crossland's (1904, p. 327) Nicidion gracilis. More- over, the change over to the longer and more arched condition of the posterior somites is much more gradual than as recorded by Crossland for his species. For the first five feet, there is a stout dorsal cirrus reaching to the tips of the bristles, and a stout conical ventral cirrus. By the loth chaetiger the dorsal cirrus is much reduced and the ventral cirrus is a conical projection on top of a glandular pad. By the 25th the dorsal cirrus is still further reduced in size and the ventral cirrus is a mere button. At the 50th chaetiger the dorsal cirrus is a slight digitiform process as in the 25th foot and the ventral cirrus is again a small conical process. The bristles agree with those figured by Treadwell. At about the 35th chaetiger the bidentate acicular chaeta appears, and at the same time the yellow aciculum gives place to a stouter black aciculum. The dental formula (Fig. 43) is 5—5 : 5 + 4—6. Details of the jaws are given in the figure. A'^. gracilis, Crossland, A^. brevis, Ehlers (1887, p. 98), and the present species are all closely allied. In addition to the diflrerences between A^. gracilis and A^. kinbergii already mentioned, Crossland makes no reference to the winged type of capillary bristle such as is present in Webster's species. Ehlers' N. brevis from Key West has slightly different upper jaws and the secondary lateral supports to the lower jaws figured by Ehlers (PI. xxi
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectscientificexpedition
