114 BULLETIN OF THE 



Mangilia quadrata var. diminuta Adams. 



These differ from the type in the greater strength of the sculpture. The 

 mouth and pillar are white. Same range as the preceding. I have distributed 

 some specimens of this under the manuscript name of corticaria before recog- 

 nizing its relations. 



Mangilia quadrata var. rugirima Dall. 



This differs from diminuta in being smaller and shorter proportionally, and 

 with the strength of the sculpture even more exaggerated. Key West. 



Mangilia quadrata var. monocingulata Dall. 



Plate XI. Fiffs. 15, 16. 



This variety differs from diminuta by having one more rib (nine in all) and 

 in having the basal cingulum obsolete so that the prominence of the posterior 

 nearly peripheral angulation though not enlarged is much more apparent. This 

 is shown in Figure 15. Figure 16 shows a further modification, in which the 

 number of primary spirals is diminished, and those that are left are less prom- 

 inent, thus making the whorls appear more rounded. Both of the specimens 

 figured are not quite adult, and hence do not show the aperture fully formed. 



Habitat. Barbados, 100 fms. 



Mangilia serga Dall. 



Plate IX. Fig. 4. 



Pkurotoma (DriUia) serga Dall, Bull. M. C. Z., IX. p. 65, August, 1881. 

 Pleurotoma {MangeJia) acanthodes Watson, Linn. See. Journ., XV. p. 433, Oct., 1881. 



Chall. Gastr., p. 342, pi. xxiii. fig. 3, 1885. 

 Pleurotoma serga Dall, Bull. M. C Z., XII. pi. ix. fig. 4, expl., 1886. 



Habitat. Bed of the Gulf Stream, Pourtales, 447 fms. Also by the U. S. 

 Fish Commission, at Station 2150, near Old Providence, in 382 fms., ooze 

 bottom temperature 56°. F. Off Bermuda, in 1075 fms,, Challenger Expedition. 



This species would appear to be identical with acanthodes, while M. corallina 

 Watson evidently belongs to this group, though I do not find its exact equiv- 

 alent among my specimens. It is within the bounds of possibility that it may 

 be an extreme variety of M. serga, especially as between my two specimens 

 of M. serga there is a notable amount of variation. 



Mangilia ? halitropis n. s. 



Shell with eight whorls and a small Sinusigera nucleus, white or ashy, with 

 a pointed spiie and broad body whorl ; surface microscopically granose or 



