THE NAUTILUS. 115 



sculptured with slender rihlets parted by wider intervals; the riblets 

 then become irregular and weaker; at and below the shoulder they 

 disappear, and the whorls are nearly smooth and flat to the last, 

 which is ribbed, the ribs rather strong but irregular on the last half 

 whorl, which is straightened, tapers to the well-rounded base, and is 

 very shortly produced forward beyond the preceding whorl. The 

 aperture is very shortly pi ri form, upper margin straightened with a 

 slight callus within near the outer angle; other margins well curved 

 and expanded. Internal axis rather wide throughout, widest above, 

 smooth, its walls slightly concave within each whorl. At the end of 

 the penultimate whorl there is a barely noticeable swelling of the 

 axis, hardly visible in some specimens, and with no superposed callus. 



Length 14.8, greatest diam. 5.8 mm.; whorls 14. 



Length 15, greatest diam. 5.9 mm.; whorls 14. 



Length 18.25, greatest diam. 5.3 mm.; whorls 13|. 



The length is estimated, since all of the examples have the peri- 

 stome more or less broken basally. While very " top-heavy," it is 

 less obese than H. imbricata v. Marts., which is strongly ribbed 

 throughout. No other species of similar shape has the same axial 

 structure. In having a large internal pillar, H. bartschi resembles 

 H.fusca v. Marts. Neither species is a typical Haplocion, but they 

 agree with no other of the defined sections of Holospira. 



This species is named for Mr. Paul Bartsch, author of an excel- 

 lent paper on Holospira and related genera. 



HOLOSPIRA GOLDMANI Bartsch. 



One example, 13x5 mm., agrees well with a cotype of this spe- 

 cies, received from the National Museum through the courtesy of 

 Dr. Ball. H. gealei H. Ad., of which the internal structure is 

 unknown, may prove to be allied. It is not unlike goldmani exter- 

 nally, so far as can be gathered from Adams' inadequate description. 



A NEW SPECIES OF PHOLADOMYA. 



BY WM. H. DALL. 



The figured type of the genus Pholadomya Sowerby is the recent 

 P. Candida Sow., from the island of Tortola in the West Indies, 

 described in 1823. A large number of fossil species are known, but 



