PROCEEDINGS OF THE NATIONAL MUSEUM 



vor* 67 



Twenty-four additional specimens, Cat. No, 361961, U.S.N.M., 

 paratypes, yield the following measurements: 



*Type. 



HOLOSPIRA (HOLOSPIRA) MONXLOVANA, new species 



Plate 1, figs. 1, 2 



Shell acicular, bluish-white. Interior of aperture brown. Nu- 

 clear whorls 23^, rather large, well rounded, smooth. The postnu- 

 clear whorls are rather narrow. The first seven increase slowly in 

 size and form a narrow cone. Tliey are m.arked by numerous, slender, 

 decidedly retractively slanting axial riblets, which are about one-third 

 as wide as the spaces that separate them. These riblets grow suc- 

 cessively weaker from the first to the seventh of these turns and on 

 the succeeding whorls, which are moderately rounded, they are indi- 

 cated at best only as lines of growth. The last whorl is marked by 

 strong, somewhat irregular, curved axial ribs, which are about as 

 wide as the spaces that separate them. Suture moderately impressed. 

 Periphery of the last whorl marked by a rather strong carina. This 

 carina is separated from the posterior portion of the whorl by a some- 

 what pinched-in zone. The last fifth of the whorl is free from the 

 preceding turn at the summit and the angle of the summit forms a 

 strong carina, while the space between it and the preceding turn, 

 that is, the outside of the parietal wall, is flattened. Anterior to the 

 peripheral carina the base slopes toward the umbilical chink, which is 

 rimate but not perforate. This portion of the base is marked by 



