1919.] NATURAL SCIENCES OF PHILADELPHIA. 27 



nent directly behind the anterior suture. Spirals equisized and 

 equispaced, narrow, sharp, much elevated lirse, prominent alike 

 on the costal and intercostal areas; lirations 4 in number on each 

 of the apical whorls, 12 or 13 upon the body and pillar which are 

 not well differentiated; the wider interspaces striated with fine, 

 even, close-set incrementals; fasciole indicated by the slightly 

 wider interspace between the posterior and the next succeeding 

 spiral. 



Aperture. — Aperture narrow, sinuous, acutely angulated pos- 

 teriorly. Outer lip broadly arcuate, feebly lirate within. Col- 

 umella excavated at the base of the body whorl. Parietal and 

 pillar wash rather thin. Pillar moderately long, slightly twisted, 

 bearing 2 equal, oblique, and rather feeble plications, midway 

 between the anterior and posterior canals. Anterior canal broad 

 and open, obtusely truncated at the extremity. 



Dimensions. — Altitude of type, 5.5 mm. Maximum diameter, 

 2.0 mm. Altitude of average individual, 3.7 mm. Maximum 

 diameter, 1.5 mm. 



Type Locality. — Natural Well, Duplin County, North Carolina. 

 Duplin ForynaUon. 



Observations. — Mitromorpha mitrodita is separated from M. 

 pyg^naea, its nearest southern relative, by the more slender out- 

 line, and the broader and less numerous costals, which, in mitrodita, 

 are not confined exclusively to the early whorls but undulate the 

 penult and even the ultima. M. smithfieldensis Olsson, the York- 

 town analogue, differs in the less numerous conchal turns, the 

 more distant axial sculpture, and the lower number of body spirals. 



Distrihution. — Duplin Formation. Natural Well, 1^ miles north 

 of Magnolia, Duplin County, North Carolina. Muldrow's Place, 

 5 miles southeast of Mayesville, Sumter County, South Carolina. 



The species is rare and, even when present, is so small that it 

 is easily overlooked. 



Collections. — U. S. National Museum. Johns Hopkins Uni- 

 versity. Academy of Natural Sciences of Philadelphia. 



Phos sloani new species. Plate I, flg. 10. 



General Characters. — Shell slender; spire greatly elevated for 

 the genus. Aperture less than two-thirds the total altitude. 

 Whorls closely appressed, almost flat, though apparently some- 

 what convex because of the greater prominence of the axial ribs 

 near the median line of the whorl. Body whorl gently rounded, 



