28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



protractively slanting and are of the same strength from the summit 

 to the periphery. Of these ribs 20 are present upon the first, 21 upon 

 the second, 22 upon the third, 26 upon the fourth, and 28 upon the 

 last whorl. At irregular intervals some of the ribs become somewhat 

 thickened, or two may become fused to form a varix. The intercostal 

 spaces are about as wide as the ribs. They are marked by 28 incised 

 transverse lines, which vary considerably in strength and spacing. 

 They are best visualized by examining our detailed sketch (pi. 6, 

 fig. 3b). The suture is well marked but not channeled. The periphery 

 is well rounded. The base is hemispherical and marked by the weaken- 

 ing axial ribs which fade out on its middle. In addition to the axial 

 ribs the base has about 14 spiral striations, which are of almost the 

 same strength and spacing. The aperture is irregularly oval; the 

 columella is thick and reflected and bears a strong fold at its inser- 

 tion ; the parietal wall is covered by a thick callus ; the outer lip bears 

 five internal folds which vary in strength and spacing. 



The type, U.S.N.M. No. 561680, conies from the Pliocene of 

 North St. Petersburg, Fla. The 5.1 whorls remaining measure: 

 Length 10.2 mm., diameter 3.7 mm. 



The huge size and fine spiral sculpture easily distinguish this spe- 

 cies from all the other known East American Mormulas. 



I take pleasure in naming this species for the late Dr. T. Wayland 

 Vaughan, whose many years of work in Tertiary paleontology, corals, 

 and oceanography have been of great help to many of us. 



MORMULA GARDNERAE, new species 



Plate 4, figures loa, b 



Shell very regularly elongate-turrited, cream-yellow. The nucleus 

 consists of about two strongly rounded whorls that form a depressed 

 helicoid spire whose axis is at right angles to that of the postnuclear 

 whorls. The postnuclear whorls are flattened and marked by strong 

 protractively slanting axial ribs, which are of the same strength from 

 the summit to the periphery where they terminate. Of these ribs 

 16 are present upon the second and third whorls and 18 upon the rest. 

 At irregular intervals some of these ribs become thickened to form 

 a weak varix. The intercostal spaces are about as wide as the ribs 

 and are marked by seven incised spiral lines, which vary in strength 

 and spacing. Our detailed sketch describes these better than words 

 (pi. 4, fig. lob). The suture is rendered wavy by the summit of the 

 axial ribs. The periphery is well rounded and marks the end of the 

 axial ribs. The base is hemispherical and without sculpture. The 



